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flashing custom rom on A/B device

Why,in custom ROMs section on 6t forum,every one of custom rom developer in his OP states DIFFERENT "Flashing instructions"?
Not a single rom dev,in his OP have same flashing instructions as some other dev! As I read more,it looks like half of them are wrong instructions,or that they don't have this device,or they don't know.
- flashing on both slots a&b?
flash OOS rom,them twrp.zip,reboot to TWRP (to any of slots),and internal will be encrypted and unreadable.Theres no way to flash on both slots in one take in TWRP or in two takes in row(with in TWRP,reboot to TWRP different slot).There's need for at least one full boot to Operating System,then back to TWRP,and internal will be visible and decrypt ed.
Many custom ROMs need OOS on both slots to be able to make them run,but this looks like nonsense to me.
- changing slots in TWRP?
let's say you flash magisk while in slot A,go to "reboot" and change slot to B, but dont reboot to TWRP.Now flash magisk.it will flash on same slot as first time,there was no slot changing.
- delete wipe "system" in TWRP,or worse "factory reset"?
it's mistake that costs me a lot of time,Ill never do it again.As all custom ROMs now have script that wipes all unnecessary files,there's no need to wipe system and screw your phone for few hours until you fix it.For me,a big No No.
best way of flashing custom os over OOS?
for me,I go into TWRP,flash custom rom,flash TWRP zip,then I reboot into TWRP and flash gapps and magisk.if internal is crypted and I can't flash gapps and magisk,I do a boot into rom,and back to TWRP to finish my flashing.wiola,it boots and works,clean rom and all is fine.
Flash back to OOS?I just go into TWRP,flash OOS ,flash twrp.zip,reboot to twrp and flash magisk.if internal is crypted,I boot into OOS,them back to TWRP,and flash everything else what I need(like magisk and kernel)
a/b devices are nothing new,but it looks to me Like on 6t is all overcomplicated.
So,tell me how you guys do it and what are yours ways of doing it right?

shawek said:
Why,in custom ROMs section on 6t forum,every one of custom rom developer in his OP states DIFFERENT "Flashing instructions"?
Not a single rom dev,in his OP have same flashing instructions as some other dev! As I read more,it looks like half of them are wrong instructions,or that they don't have this device,or they don't know.
- flashing on both slots a&b?
flash OOS rom,them twrp.zip,reboot to TWRP (to any of slots),and internal will be encrypted and unreadable.Theres no way to flash on both slots in one take in TWRP or in two takes in row(with in TWRP,reboot to TWRP different slot).There's need for at least one full boot to Operating System,then back to TWRP,and internal will be visible and decrypt ed.
Many custom ROMs need OOS on both slots to be able to make them run,but this looks like nonsense to me.
- changing slots in TWRP?
let's say you flash magisk while in slot A,go to "reboot" and change slot to B, but dont reboot to TWRP.Now flash magisk.it will flash on same slot as first time,there was no slot changing.
- delete wipe "system" in TWRP,or worse "factory reset"?
it's mistake that costs me a lot of time,Ill never do it again.As all custom ROMs now have script that wipes all unnecessary files,there's no need to wipe system and screw your phone for few hours until you fix it.For me,a big No No.
best way of flashing custom os over OOS?
for me,I go into TWRP,flash custom rom,flash TWRP zip,then I reboot into TWRP and flash gapps and magisk.if internal is crypted and I can't flash gapps and magisk,I do a boot into rom,and back to TWRP to finish my flashing.wiola,it boots and works,clean rom and all is fine.
Flash back to OOS?I just go into TWRP,flash OOS ,flash twrp.zip,reboot to twrp and flash magisk.if internal is crypted,I boot into OOS,them back to TWRP,and flash everything else what I need(like magisk and kernel)
a/b devices are nothing new,but it looks to me Like on 6t is all overcomplicated.
So,tell me how you guys do it and what are yours ways of doing it right?
Click to expand...
Click to collapse
I agree with you!!! This is a mess

even though I have flashed thousands of roms over the years, since I got rid of my Nexus 6, I havent had a phone that I could flash roms on, so, after dumping my Note 8 for this great phone, I was very hesitant to flash a custom rom, for all the reasons you have mentioned..
So, my question is, can you flash ANY of these custom roms by using the clear method that you mentioned in the OP?
If on one of the beta releases, is the procedure the same as I am showing below, or, do you always have to first return to stock OOS?
In my years of flashing dozens of phones, you never had to go back to "stock" if you wiped everything before flashing, but, it seems like on several of these roms, you are instructed to first return to "stock", THEN flash the new custom rom...
Plus, some roms say to wipe everything before you flash, and others say not to wipe system, or not to wipe data...
Unless I am nuts, I always thought that you wipe everything before converting to a totally new rom, but, maybe I am wrong here too..
"for me,I go into TWRP,flash custom rom,flash TWRP zip,then I reboot into TWRP and flash gapps and magisk.if internal is crypted and I can't flash gapps and magisk,I do a boot into rom,and back to TWRP to finish my flashing.wiola,it boots and works,clean rom and all is fine."
These instructions seem pretty clear and concise, hopefully, they are correct, and we can just use this exact method and be done with it!
No mention of wiping in your directions...what do YOU wipe before flashing a new custom rom?
Hopefully, this gets cleared up once and for all, and we can ask the MODS to make a sticky of the ACTUAL CORRECT INSTRUCTIONS>>
thanks

wase4711 said:
"for me,I go into TWRP,flash custom rom,flash TWRP zip,then I reboot into TWRP and flash gapps and magisk.if internal is crypted and I can't flash gapps and magisk,I do a boot into rom,and back to TWRP to finish my flashing.wiola,it boots and works,clean rom and all is fine."
These instructions seem pretty clear and concise, hopefully, they are correct, and we can just use this exact method and be done with it!
No mention of wiping in your directions...what do YOU wipe before flashing a new custom rom?
Hopefully, this gets cleared up once and for all, and we can ask the MODS to make a sticky of the ACTUAL CORRECT INSTRUCTIONS>>
thanks
Click to expand...
Click to collapse
-if on custom rom,probably it's good to first go to stock OOS and then to another custom rom.but this is also strange to me,as I don't understand what are benefits of this.i also read this,Google heh.i tried going from AOSCP to PixelEcpirince without flashing OOS in-between process,all was fine.
-I haven't been on Beta OOS yet,only stable.But that thing bout "before flashing custom rom,flash stable OOS even if your on Beta OOS" is also a big question to me.they are practically the same,both are latest OOS,one maybe more stable them other,but this also can be discussed hehe
-i don't wipe anything!! when my custom rom boots,I go into it's settings, without setting my Google account and other stuff, and I do "factory reset"( not in TWRP,in custom rom's settings!).Phone reboots,and all is fine,clean beginning,TWRP works,root works.About unwantedFolders in internal storage,I delete them manualy.

Only thing in my experience to wipe in TWRP is DATA,but this is also questionable,as I run into problems also doing data wipe I TWRP.
Now ROMs(maybe only for a/b devices) have scripts that wipe previous System during flashing new rom,so we don't have to do a Clean Flash anymore.
I'm also confused,more I read,less I understand ?

I like the idea of wiping via factory reset, once the rom boots, but, if it does NOT boot, then you wouldnt be able to do it that way..
I guess flashing an OOS based rom over an OOS based rom would always allow you to boot, if done right..
But, roms like RR, Carbon, AICP, and a couple others that have shown up here recently were never really OOS based roms, but AOSP based, at least I thought so..
the more I think about this, the more confusing it seems to get..

wase4711 said:
I like the idea of wiping via factory reset, once the rom boots, but, if it does NOT boot, then you wouldnt be able to do it that way..
I guess flashing an OOS based rom over an OOS based rom would always allow you to boot, if done right..
But, roms like RR, Carbon, AICP, and a couple others that have shown up here recently were never really OOS based roms, but AOSP based, at least I thought so..
the more I think about this, the more confusing it seems to get..
Click to expand...
Click to collapse
This is from the pixel 2 xl forum another a/b device
First time installing Pixel Dust ROM, or coming from another ROM:
As mentioned above, you are required to flash stock ROM before installing this custom ROM.
1. Flashing Stock ROM:
Follow these instructions: https://developers.google.com/android/images#taimen
2. Flashing PixelDust ROM:
Reboot to twrp
Wipe Dalvik cache and Data partitions
Flash ROM
Flash twrp zip
Reboot to System and enjoy the Pixel Dust Goodness!
Flashing Magisk:
You cannot flash Magisk during the initial install. You must boot into PixelDust ROM at least once!
Reboot to Recovery
Flash Magisk-v17.x.zip
Reboot to System

shawek said:
Why,in custom ROMs section on 6t forum,every one of custom rom developer in his OP states DIFFERENT "Flashing instructions"?
Not a single rom dev,in his OP have same flashing instructions as some other dev! As I read more,it looks like half of them are wrong instructions,or that they don't have this device,or they don't know.
- flashing on both slots a&b?
flash OOS rom,them twrp.zip,reboot to TWRP (to any of slots),and internal will be encrypted and unreadable.Theres no way to flash on both slots in one take in TWRP or in two takes in row(with in TWRP,reboot to TWRP different slot).There's need for at least one full boot to Operating System,then back to TWRP,and internal will be visible and decrypt ed.
Many custom ROMs need OOS on both slots to be able to make them run,but this looks like nonsense to me.
- changing slots in TWRP?
let's say you flash magisk while in slot A,go to "reboot" and change slot to B, but dont reboot to TWRP.Now flash magisk.it will flash on same slot as first time,there was no slot changing.
- delete wipe "system" in TWRP,or worse "factory reset"?
it's mistake that costs me a lot of time,Ill never do it again.As all custom ROMs now have script that wipes all unnecessary files,there's no need to wipe system and screw your phone for few hours until you fix it.For me,a big No No.
best way of flashing custom os over OOS?
for me,I go into TWRP,flash custom rom,flash TWRP zip,then I reboot into TWRP and flash gapps and magisk.if internal is crypted and I can't flash gapps and magisk,I do a boot into rom,and back to TWRP to finish my flashing.wiola,it boots and works,clean rom and all is fine.
Flash back to OOS?I just go into TWRP,flash OOS ,flash twrp.zip,reboot to twrp and flash magisk.if internal is crypted,I boot into OOS,them back to TWRP,and flash everything else what I need(like magisk and kernel)
a/b devices are nothing new,but it looks to me Like on 6t is all overcomplicated.
So,tell me how you guys do it and what are yours ways of doing it right?
Click to expand...
Click to collapse
You make it overcomplicated.
To flash both slots you only need to do a complete reboot to make sure the OS is not hosed.
You do that so if it is you can use the other slot. This is not necessary.
You flash in TWRP, change the slot and reboot into TWRP and flash the other slot.
It could be easier if TWRP allowed flashing on the inactive slot.
But, even if you are rooted and want to upgrade it is suggested to upgrade both slots.
I think it's just a minor pain. There are bigger problems.

tech_head said:
You make it overcomplicated.
To flash both slots you only need to do a complete reboot to make sure the OS is not hosed.
You do that so if it is you can use the other slot. This is not necessary.
You flash in TWRP, change the slot and reboot into TWRP and flash the other slot.
It could be easier if TWRP allowed flashing on the inactive slot.
But, even if you are rooted and want to upgrade it is suggested to upgrade both slots.
I think it's just a minor pain. There are bigger problems.
Click to expand...
Click to collapse
it's not a minor pain if most of time that I go to flash custom rom,I lost all my 60-80gigs of internal data, cuz of failed decryption,or failed rom flash,or failed TWRP flash.There were times when I did Factory reset in TWRP,flashed OOS,flashed TWRP.zip,did reboot to recovery,and I lost recovery.I was left with bootloader (fastboot) and had to fastbooting OOS few times(which led to full wipe of internal storage).OOS wasn't even flashed,or TWRP wanst even flashed.And I just followed instructions.
this are the things that I'm talking about.Even if I follow instructions, instructions are not detailed.
now I probably know how to do it right,,but still...I learned it hard way,and still learning
thanks for your opinion and answer:good:

shawek said:
it's not a minor pain if most of time that I go to flash custom rom,I lost all my 60-80gigs of internal data, cuz of failed decryption,or failed rom flash,or failed TWRP flash.There were times when I did Factory reset in TWRP,flashed OOS,flashed TWRP.zip,did reboot to recovery,and I lost recovery.I was left with bootloader (fastboot) and had to fastbooting OOS few times(which led to full wipe of internal storage).OOS wasn't even flashed,or TWRP wanst even flashed.And I just followed instructions.
this are the things that I'm talking about.Even if I follow instructions, instructions are not detailed.
now I probably know how to do it right,,but still...I learned it hard way,and still learning
thanks for your opinion and answer:good:
Click to expand...
Click to collapse
I understand now.
The instructions are not clear for most of this stuff and you can screw up.
If something fails to flash, there are very few reasons to ever completely wipe. Even a factory reset does not require a complete wipe of data.
I would suggest at all times keeping a boot image of the current OS you are using.
I would also suggest keeping a TWRP.img on your computer. You can always boot from a TWRP image even if it's not the one you want to install.
That will at least get decryption and the ability to flash.
I don't flash custom ROMs, because the stock one with root does what I need. Also the fingerprint sensor is not guaranteed under custom ROMs and I need that to work.

no verify opt on most after data wipe or that brands version of it, then reboot to twrp verify is still not there because twrp will say no os installed the avb changed things every phone is different depending on their security Samsung for one

Try this guide. Read the first paragraph if you have problems with decryption.

Boot twrp
Wipe dalvik and data
Flash rom+twrp
Reboot SYSTEM!
Boot back to recovery
Factory reset
Flash gapps+magisk
Reboot and done
No data loss or PC needed...

So here's some food for thought. I read somewhere that when you install a ROM zip via TWRP it actually Installs to the Inactive Slot. And when you reboot to TWRP after reflashing the Installer it Switches Slots and then you can Flash GAPPS etc. But what if someone were to flash the ROM twice ; once to each slot? Would be noice if We can use this to Multi-Boot Two ROMs at once....

Mannan Qamar said:
So here's some food for thought. I read somewhere that when you install a ROM zip via TWRP it actually Installs to the Inactive Slot. And when you reboot to TWRP after reflashing the Installer it Switches Slots and then you can Flash GAPPS etc. But what if someone were to flash the ROM twice ; once to each slot? Would be noice if We can use this to Multi-Boot Two ROMs at once....
Click to expand...
Click to collapse
I think that question was asked in one of the threads in here "can use this to Multi-Boot Two ROMs at once" and I don't think it's possible. I'm sorry I don't remember the thread it was in. You might try Google.

It's wise to do the oos in both slots which you can switch slots without rebooting fyi because when you flash a custom ROM no matter if you switch back to a it'll flash magisk and probably gapps in the inactive slot. If you try to return the custom ROM to slot a after it flashes it will say insufficient room for gapps and such. So to me it seems this makes it a clean slate so it can flash to inactive slot. Hope that clears up why they encourage the double oos flash

Everyone, I think you have almost helped me figure out how I screwed up my 6T. I made a post needing help but this thread I believe is the answer. I wanted to install lineage16 but opted for Resurrection Remix since that dev claimed the fingerprint reader worked. To make a long story short, I flashed the latest .15 OxyOS update first, switched partitions via TWRP and flashed it again, them flashed TWRP and rebooted to recovery. Flashed Remix then TWRP again and rebooted to Remix. Now I have no room for anything in storage although it's only 25% full and my file explorer cannot access any storage not can I update apps through play store or anything. I have the latest OxyOS on my OTG flash drive as well as TWRP and magisk, but every time I find a thread on hope to do an installation, it varies and I keep coming back to this storage issue. Can someone PLEASE link me out tell me where to find the correct process to now start from the beginning and get my phone back working on the OxyOS .15 stock rom? Thank you very much and I'm glad I found this thread because it finally makes sense as to how misinformation is causing many people to have issues.

SuperUnkn0wn0ne said:
Everyone, I think you have almost helped me figure out how I screwed up my 6T. I made a post needing help but this thread I believe is the answer. I wanted to install lineage16 but opted for Resurrection Remix since that dev claimed the fingerprint reader worked. To make a long story short, I flashed the latest .15 OxyOS update first, switched partitions via TWRP and flashed it again, them flashed TWRP and rebooted to recovery. Flashed Remix then TWRP again and rebooted to Remix. Now I have no room for anything in storage although it's only 25% full and my file explorer cannot access any storage not can I update apps through play store or anything. I have the latest OxyOS on my OTG flash drive as well as TWRP and magisk, but every time I find a thread on hope to do an installation, it varies and I keep coming back to this storage issue. Can someone PLEASE link me out tell me where to find the correct process to now start from the beginning and get my phone back working on the OxyOS .15 stock rom? Thank you very much and I'm glad I found this thread because it finally makes sense as to how misinformation is causing many people to have issues.
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Click to collapse
You may have solved this by now, but I found that using the MSM Download Tool has enabled me to return to stock OxygenOS even after getting stuck in a boot loop. I've not been able to successfully flash RR or LineageOS however, still getting stuck in said boot loop...

can somebody explain flashing roms on a/b devices?

I'm no stranger to rooting and ROM'ing I've been doing it for years now. However I've never had an a/b device and it's confusing me I have a T-Mobile variant switched to international the bootloader is unlocked I'm rooted with magisk 18.1, and TWRP 3.3.0-2 and I have OOS 9.0.12 installed. I don't understand having OOS as a base ROM for other custom ROMs, some people say to flash OOS twice because apparently it goes into both slot a and b but then twrp encrypts data forcing you to msmtool. I know to take any password and finger print off the phone before switching ROMs and to change the lock screen to none.
My understanding of the steps to follow are
Reboot into TWRP
Wipe like you normally would
Flash custom ROM if your choosing
Flash TWRP (so you don't lose TWRP)
Reboot into the ROM
Reboot into recovery and flash magisk and gapps if needed
Reboot and everything should be good
If that's correct please let me know and I appreciate the help

Joe199799 said:
I'm no stranger to rooting and ROM'ing I've been doing it for years now. However I've never had an a/b device and it's confusing me I have a T-Mobile variant switched to international the bootloader is unlocked I'm rooted with magisk 18.1, and TWRP 3.3.0-2 and I have OOS 9.0.12 installed. I don't understand having OOS as a base ROM for other custom ROMs, some people say to flash OOS twice because apparently it goes into both slot a and b but then twrp encrypts data forcing you to msmtool. I know to take any password and finger print off the phone before switching ROMs and to change the lock screen to none.
My understanding of the steps to follow are
Reboot into TWRP
Wipe like you normally would
Flash custom ROM if your choosing
Flash TWRP (so you don't lose TWRP)
Reboot into the ROM
Reboot into recovery and flash magisk and gapps if needed
Reboot and everything should be good
If that's correct please let me know and I appreciate the help
Click to expand...
Click to collapse
First you need to flash OOS stable because of vendor and second to avoid the bugs. If you flash open beta u will face alot of face issues that why stable is always recommend to flash before flashing ROM and it's also must to flash before flashing ROM again same thing to avoid bugs but it's personal choice if u flash Rom and face any Issue flash OOS stable and then flash Rom. If u don't flash OOS and u didn't face any Issue you are fine that's my experience so far if I flash issue I repeat but stable first then custom and 99% bugs fixed that I "Only" face ..
And method yes that is correct for flashing ROM at least for me I followed always and nothing happens!

farhan20 said:
First you need to flash OOS stable because of vendor and second to avoid the bugs. If you flash open beta u will face alot of face issues that why stable is always recommend to flash before flashing ROM and it's also must to flash before flashing ROM again same thing to avoid bugs but it's personal choice if u flash Rom and face any Issue flash OOS stable and then flash Rom. If u don't flash OOS and u didn't face any Issue you are fine that's my experience so far if I flash issue I repeat but stable first then custom and 99% bugs fixed that I "Only" face ..
And method yes that is correct for flashing ROM at least for me I followed always and nothing happens!
Click to expand...
Click to collapse
I flashed OOS 9.0.12 yesterday because I switched ROMS with 9.0.11 and it resulted in a msm flash, turns out switching roms from 9.0.11 is a bad idea. But after updating I flashed havoc OS and everything is all good. We appreciate the answer I understand it a little better now

A/B slotting implies having a pair of partitions for most partition types (eg., Boot, System, etc...). This does not include the Data partition, however. The purpose was never to allow the coexistence of multiple ROMs but to install an OTA stock update into the unused slot while you're already using the ROM. That way if there's an error during the update process, the OS can choose not to switch over to the updated partition on reboot and continue using the current one. This redundancy is why they were able and willing to scrap the Recovery partition, too.
When flashing a ROM for an A/B device, it actually flashes to the slot you are currently not using. Then upon reboot, it switches to that slot. This is why to maintain TWRP, you need to run TWRP installer after flashing the ROM but before the reboot. Otherwise, restarting into recovery would restart into the ROMs recovery or stock recovery. The TWRP installer unconditionally patches tho Boot partition of both slots. Note that other installers like Magisk and GApps do not. If you were to install Magisk before rebooting, it would install to the currently active slot, not the one the ROM was installed to.
After flashing the ROM and TWRP and rebooting into recovery, the slot would then be set to the newly installed ROM's slot and you can finish installing Magisk and/or GApps. You would wipe data unless you're dirty flashing an updated ROM. If you've removed security password/pin/pattern before flashing it's safe to flash before rebooting in recovery. In situations where I still had such security on, I had to wipe data after rebooting into recovery to maintain working decryption. Taking off the password/pin/pattern before flashing effectively disables the encryption of files on the data partition making it easier to transition to another ROM without any decryption problems.
Whether you need to flash OOS before flashing a ROM, I presume, would depend on whether the ROM, itself, is OOS based. It's not necessary for a non-OOS ROMs. There is a nasty problem that creeps up with OOS based ROMs in which it might boot-loop into recovery. I assume the double flashing might prevent that, though my experience with that problem is after a TWRP restore of OOS stock. You could use msmtool in such a situation as stated, but I always get rid of it by flashing stock Boot partition in fastboot, booting into stock recovery, and factory reset + erase sdcard.
Reboot into TWRP
Wipe like you normally would
Flash custom ROM if your choosing
Flash TWRP (so you don't lose TWRP)
Reboot into the ROM
Reboot into recovery and flash magisk and gapps if needed
Reboot and everything should be good.
Click to expand...
Click to collapse
Don't reboot into ROM before reboot into recovery and make sure to take off Pin/Password/Pattern/Fingerprints before booting into TWRP. Otherwise, this should be fine. For the wipe stage, you don't even need to wipe System or Boot (never Boot), in my experience. Just Data and Dalvik, if not dirty flashing the same ROM type.

Nsane457 said:
A/B slotting implies having a pair of partitions for most partition types (eg., Boot, System, etc...). This does not include the Data partition, however. The purpose was never to allow the coexistence of multiple ROMs but to install an OTA stock update into the unused slot while you're already using the ROM. That way if there's an error during the update process, the OS can choose not to switch over to the updated partition on reboot and continue using the current one. This redundancy is why they were able and willing to scrap the Recovery partition, too.
When flashing a ROM for an A/B device, it actually flashes to the slot you are currently not using. Then upon reboot, it switches to that slot. This is why to maintain TWRP, you need to run TWRP installer after flashing the ROM but before the reboot. Otherwise, restarting into recovery would restart into the ROMs recovery or stock recovery. The TWRP installer unconditionally patches tho Boot partition of both slots. Note that other installers like Magisk and GApps do not. If you were to install Magisk before rebooting, it would install to the currently active slot, not the one the ROM was installed to.
After flashing the ROM and TWRP and rebooting into recovery, the slot would then be set to the newly installed ROM's slot and you can finish installing Magisk and/or GApps. You would wipe data unless you're dirty flashing an updated ROM. If you've removed security password/pin/pattern before flashing it's safe to flash before rebooting in recovery. In situations where I still had such security on, I had to wipe data after rebooting into recovery to maintain working decryption. Taking off the password/pin/pattern before flashing effectively disables the encryption of files on the data partition making it easier to transition to another ROM without any decryption problems.
Whether you need to flash OOS before flashing a ROM, I presume, would depend on whether the ROM, itself, is OOS based. It's not necessary for a non-OOS ROMs. There is a nasty problem that creeps up with OOS based ROMs in which it might boot-loop into recovery. I assume the double flashing might prevent that, though my experience with that problem is after a TWRP restore of OOS stock. You could use msmtool in such a situation as stated, but I always get rid of it by flashing stock Boot partition in fastboot, booting into stock recovery, and factory reset + erase sdcard.
Don't reboot into ROM before reboot into recovery and make sure to take off Pin/Password/Pattern/Fingerprints before booting into TWRP. Otherwise, this should be fine. For the wipe stage, you don't even need to wipe System or Boot (never Boot), in my experience. Just Data and Dalvik, if not dirty flashing the same ROM type.
Click to expand...
Click to collapse
That was a very well written and insightful answer thank you. The way you wrote makes everything much easier to understand

I think with the new TWRP recovery flashing is about to be less of a d**k. TWRP 3.3.0-0

Won't boot custom ROMs

So far there's only a small sample, but I think there's enough of a pattern to constitute an issue. I've tried to flash the latest of both pixel experience (unofficial) and havoc, and each one sends me directly to either recovery or fastboot, depending on the order which I flash/wipe/factory reset. It's been a couple months since I've flashed anything other than an open beta update, but I never had any issues flashing ROMs.
For both I've tried:
Flash OOS. 9.0.13 (or OB13) in both slots
Flashed Twrp installer
Reboot to recovery
Flash custom ROM
Flash Twrp installer
Factory reset (tried full wipe as well)
It's at this point where I attempt to reboot to recovery to flash gapps (for havoc, not PE) I get sent to recovery or fastboot, depending on whether I reset or wipe data.
I can flash OOS and boot stable or open beta and boot into them with no problems. I've even allowed it to boot to the OOS welcome screen and went back to recovery to flash the custom ROM with the same outcome, doing a factory reset before I flash, after I flash, reboot to recover after flashing to factory reset. I've tried a full wipe in place of factory reset and all different combinations, all with the same result...
What am I missing?

lordcheeto03 said:
What am I missing?
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Click to collapse
I think I've had this issue also--it might be necessary to let the OOS ROM boot up as system--no need to setup the phone, then reboot yourself to TWRP and flash whatever else you want.
It was confusing to me too, and I didn't take notes, so don't know exactly what happened.
Also, maybe don't try to flash things to both partitions--just let the installers do their work as they are made to do without any extra steps.
Since you've already factory reset/wiped, it might help to skip this step also, as a trial.
Did you have Magisk before, and uninstall it first? Might help, as uninstalling restores system images or somesuch.
And, there are some occasions where a ROM flash won't reboot properly without first installing Magisk, but don't recall the incidentals of this either.
Regardless, we'll have a record if you post what steps succeeded in your case.

pbergonzi said:
I think I've had this issue also--it might be necessary to let the OOS ROM boot up as system--no need to setup the phone, then reboot yourself to TWRP and flash whatever else you want.
It was confusing to me too, and I didn't take notes, so don't know exactly what happened.
Also, maybe don't try to flash things to both partitions--just let the installers do their work as they are made to do without any extra steps.
Since you've already factory reset/wiped, it might help to skip this step also, as a trial.
Did you have Magisk before, and uninstall it first? Might help, as uninstalling restores system images or somesuch.
And, there are some occasions where a ROM flash won't reboot properly without first installing Magisk, but don't recall the incidentals of this either.
Regardless, we'll have a record if you post what steps succeeded in your case.
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Click to collapse
Everywhere I've read says to flash OOS to both partitions so if there's an issue with the custom ROM there's a fallback.. I don't flash the custom ROM to both partitions, only OOS. Also, I've tried letting OOS boot to the welcome screen, then back to recovery; I didn't do any setup.
I have magisk installed in OOS, though I haven't tried flashing it when flashing the ROMs. When flashing ROMs I've always flashed the ROM and Twrp, reboot straight to recovery, and flash gapps/Magisk. In my experience, I've been able to skip rebooting back to recovery to flash Magisk and gapps and just boot straight to the barebones ROM.
To reiterate, I use the exact same process to flash OOS and it works flawlessly; can flash the stable or open beta, no issues. It's only non-OOS that refuses to work correctly.
I'm wondering if I need to use the unbrick tool and start from a 100% clean slate .. something may be borked that an unbrick may fix, it's about the only option left that I can think of...

lordcheeto03 said:
Everywhere I've read
Click to expand...
Click to collapse
Good luck whatever you do.

pbergonzi said:
Good luck whatever you do.
Click to expand...
Click to collapse
Thank you for the ideas

I ran the unbrick tool and still encountered the issues, but I did learn something, and also finally got havoc to boot, although I'm still unsure exactly what I did. I'm not saying I figured out exactly what is wrong, and I can't say I know the exact solution, but I CAN say I believe the solution lies somewhere within this wall I'm typing.,..
I noticed this earlier but it didn't actually click until I still got the same error after the unbrick tool... I would always boot correctly to OOS on slot b, so after every successful boot, I'd go into recovery and try flashing.. now taking into account the fact that I flashed OOS in both slots is important because on a successful boot, which would be slot b, I'd go into recovery, still on slot b, so that's the first slot to get OOS. Change slots, flash to slot a, then boot to OOS. If I'm remembering how a/b partitions go, since slot A was the last slot to flash, it would automatically fall back to slot b to boot. Hence the successful boot. Go back to recovery, flash havoc on b, it would attempt to boot from a, and fail.. go back to recovery, I'm back on slot b to start the process over.
After still encountering the problem after the unbrick, I really began paying attention to the boot slots. Once I was paying attention to that, I attempted to manually boot from slot a after flashing OOS to both slots and I got sent to a screen that says Qualcomm crashdump mode. Power +vol up/dn to force a reboot, then volume down until the bootloader unlocked splash screen to go to recovery.
Now this is what I think I did... After figuring out it was the slot, I believe I formatted slot a, and due to the way it fell, slot b then began being the slot to mess up so i made sure to flash havoc/twrp installer in the slot a and it booted right up. Went back to recovery to flash magisk and gapps, and finally a factory reset. Boot from slot a, and here I am.
There were times where I would get stuck in fastboot, boot to recovery or system would just send me to fastboot.. I guess that also meant I was booting from the bad slot. I tried fastboot boot twrp.img, it would send it, but fail to authenticate. Fixed that by doing fastboot --set-active=b then I could restart back to recovery no problem.

flashing 10.3

Hey guys
I made a post and got no replies but have been looking into it more and remember I need adb to flash the 10.3 update, I've got all the files ready but from reading I'm confused as to how to flash via adb.
I've read you need the phone in twrp while doing flashing you need to flash the other slot blah blah blah , doesn't make sense to me...
Can anyone help me out? I've seen stuff has changed since the 10 update and I'm at a loss right now..
Thanks for any help in advance

CptUnicorns said:
Hey guys
I made a post and got no replies but have been looking into it more and remember I need adb to flash the 10.3 update, I've got all the files ready but from reading I'm confused as to how to flash via adb.
I've read you need the phone in twrp while doing flashing you need to flash the other slot blah blah blah , doesn't make sense to me...
Can anyone help me out? I've seen stuff has changed since the 10 update and I'm at a loss right now..
Thanks for any help in advance
Click to expand...
Click to collapse
You nearly never need adb to update.... Dable in some circumstances with fastboot.
Just...update. You don't specify what OS you run now, rooted , twrp etc...
Read my thread about OOS stable in Guide News section and ask there if it's not clear

Striatum_bdr said:
You nearly never need adb to update.... Dable in some circumstances with fastboot.
Just...update. You don't specify what OS you run now, rooted , twrp etc...
Read my thread about OOS stable in Guide News section and ask there if it's not clear
Click to expand...
Click to collapse
Cheers. I've read to much and watch to many videos and I've just completely confused myself buddy. I'll check your post out now someone else linked me to a proper guide I was unable to use.
I'm on havoc right, magisk 20 and twrp 3.2.3-2

CptUnicorns said:
Cheers. I've read to much and watch to many videos and I've just completely confused myself buddy. I'll check your post out now someone else linked me to a proper guide I was unable to use.
I'm on havoc right, magisk 20 and twrp 3.2.3-2
Click to expand...
Click to collapse
You're seriously late in versions of TWRP and Magisk. Update twrp with latest installer.
Then in twrp flash OOS, then twrp installer again
Reboot to recovery to switch slots
Flash again OOS and TWRP installer again
Reboot to twrp and flash Magisk then reboot system
If there's issues with encryption in recovery you can eventually use an OTG disk if you have one or ADB sideload
Last possibility is fastbooting oos ROM

Striatum_bdr said:
You're seriously late in versions of TWRP and Magisk. Update twrp with latest installer.
Then in twrp flash OOS, then twrp installer again
Reboot to recovery to switch slots
Flash again OOS and TWRP installer again
Reboot to twrp and flash Magisk then reboot system
If there's issues with encryption in recovery you can eventually use an OTG disk if you have one or ADB sideload
Last possibility is fastbooting oos ROM
Click to expand...
Click to collapse
Brilliant thanks! I've updated twrp and magisk now, had no internet so couldn't update. Do I not need to wipe the internal storage at all when flashing stock oos ontop of havoc?
And for the slot just so I know for certain;
I flash slot A with oos, twrp.
Now I reboot go to slot B, do the exact same.
Reboot again, flash new ROM , twrp/magisk.
Profit? I read you post detailing the slots, that's the part that confuses me. I'm going to have another read so I fully understand what I am actually doing instead of doing everything blind.

CptUnicorns said:
Brilliant thanks! I've updated twrp and magisk now, had no internet so couldn't update. Do I not need to wipe the internal storage at all when flashing stock oos ontop of havoc?
And for the slot just so I know for certain;
I flash slot A with oos, twrp.
Now I reboot go to slot B, do the exact same.
Reboot again, flash new ROM , twrp/magisk.
Profit? I read you post detailing the slots, that's the part that confuses me. I'm going to have another read so I fully understand what I am actually doing instead of doing everything blind.
Click to expand...
Click to collapse
Anytime you go from AOSP to OOS, or back you generally have to wipe DATA. If you don't OOS will dump you off at recovery, wipe data and then it will boot generally.
As for the slots, when flashing a ROM it always flashes to the opposite slot. So if you are currently on Slot A and you flash a ROM, it will flash to Slot B. The ROM will also overwrite install it's own recovery. So you install TWRP again if you want. Then you reboot to recovery, it will automatically switch to the new slot since you installed a new ROM. Now on the slot where the new ROM is installed, we could install Magisk or Gapps, things like that if needed. If we wanted to update the original slot (A) we would install the ROM again. As well as TWRP again. Reboot to recovery again, Magisk, etc.
ROMs install to opposite slots. After a ROM installation, rebooting to recovery will switch slots for you. Most other items install to the current slot (that is why you need to reboot before install things like Magisk, Gapps, etc). Hopefully that helps clarify things? If not ask.

OhioYJ said:
Anytime you go from AOSP to OOS, or back you generally have to wipe DATA. If you don't OOS will dump you off at recovery, wipe data and then it will boot generally.
As for the slots, when flashing a ROM it always flashes to the opposite slot. So if you are currently on Slot A and you flash a ROM, it will flash to Slot B. The ROM will also overwrite install it's own recovery. So you install TWRP again if you want. Then you reboot to recovery, it will automatically switch to the new slot since you installed a new ROM. Now on the slot where the new ROM is installed, we could install Magisk or Gapps, things like that if needed. If we wanted to update the original slot (A) we would install the ROM again. As well as TWRP again. Reboot to recovery again, Magisk, etc.
ROMs install to opposite slots. After a ROM installation, rebooting to recovery will switch slots for you. Most other items install to the current slot (that is why you need to reboot before install things like Magisk, Gapps, etc). Hopefully that helps clarify things? If not ask.
Click to expand...
Click to collapse
That does clear up things for me, I've either mis-read or not read that when on slot A you are actually flashing slot B and Visa versa.
I'll be flashing both my slots to 10.3.1 just so they're fully updated. ( A is my main)
Finally part from me, when I'm going to flash my custom ROM (havoc again) I've just got to repeat said steps but flashing havoc instead of OOS then on the last reboot, recovery and magisk?

CptUnicorns said:
Finally part from me, when I'm going to flash my custom ROM (havoc again) I've just got to repeat said steps but flashing havoc instead of OOS then on the last reboot, recovery and magisk?
Click to expand...
Click to collapse
Fair warning, I don't use Havoc. I use Lineage, here is how I install AOSP ROMs, (link) However, yes, on the final reboot would be when you install Magisk (Gapps as well if you need them). In theory recovery should already be installed, but installing it again won't hurt anything (installing recovery wipes out Magisk, so install Magisk after recovery if you do that). Remember you need Havoc on both slots (you don't want OOS on one and Havoc on another). So flash it twice.

OhioYJ said:
Fair warning, I don't use Havoc. I use Lineage, here is how I install AOSP ROMs, (link) However, yes, on the final reboot would be when you install Magisk (Gapps as well if you need them). In theory recovery should already be installed, but installing it again won't hurt anything (installing recovery wipes out Magisk, so install Magisk after recovery if you do that). Remember you need Havoc on both slots (you don't want OOS on one and Havoc on another). So flash it twice.
Click to expand...
Click to collapse
Great stuff. Thought I understood from how you explained it. I'll check that guide as well and have it to hand just incase.

OhioYJ said:
Fair warning, I don't use Havoc. I use Lineage, here is how I install AOSP ROMs, (link) However, yes, on the final reboot would be when you install Magisk (Gapps as well if you need them). In theory recovery should already be installed, but installing it again won't hurt anything (installing recovery wipes out Magisk, so install Magisk after recovery if you do that). Remember you need Havoc on both slots (you don't want OOS on one and Havoc on another). So flash it twice.
Click to expand...
Click to collapse
Something didnt want to play when I was flashing... Got to flashing gapps and magisk, gapps flash gave me a error 64 and i got magisk installed, booted, now I've got no twrp and when I use fastboot it just softbricks then restarts after about 5 minutes, I'm gonna try booting from 3.2.3-2 as that was fine and hope I can boot into recovery and just go lineage I think for something new
EDIT
So I used fastboot --set-active=a, managed to get back to twrp so now its flashed on both again. In the process of flashing lineage now, hopefully this wont chuck another error at me for gapps

OnePlus 6t Wifi Issue on custom roms

Okay so I've tried Pixel experience, lineage os , omni rom treskmod and couple of other custom android 10 roms, all stable and official and also updated ones, the wifi just simply doesn't work, wifi hotspot won't turn on either. I've tried every solution on the internet. I've even factory reset my phone using msm download tool and no luck(did this countless times).
I'm back in OOS 10.3.2 and there's no issue apparently.
At one point , i flashed a custom rom and the wifi didn't work, so I flashed OOS in the two slots and checked , the wifi works in OOS apparently, and never in custom roms.
Has anyone got this issue before and knows a solution?

How is your installation procedure?

onliner said:
How is your installation procedure?
Click to expand...
Click to collapse
I flash OOS and twrp on both slots, reboot recovery,
And then flash the rom and twrp, reboot recovery,then format data and factory reset, reboot recovery, if needed for some gapps, then reboot system

ivanthomas said:
I flash OOS and twrp on both slots, reboot recovery,
And then flash the rom and twrp, reboot recovery,then format data and factory reset, reboot recovery, if needed for some gapps, then reboot system
Click to expand...
Click to collapse
That's a lot of unnecessary steps. OOS on both slots, reboot to bootloader, boot twrp, format data and flash the custom rom, reboot bootloader, boot twrp and flash gapps, don't install twrp permanently if you are not going to install Magisk.

onliner said:
That's a lot of unnecessary steps. OOS on both slots, reboot to bootloader, boot twrp, format data and flash the custom rom, reboot bootloader, boot twrp and flash gapps, don't install twrp permanently if you are not going to install Magisk.
Click to expand...
Click to collapse
I need magisk too, I usually permanently install twrp
Also you think it's the way I'm installing at fault here? Or the rom? Or is it something wrong with my device?

ivanthomas said:
it's the way I'm installing at fault here?
Click to expand...
Click to collapse
This.
I always install roms with the procedure i said above and have never had any problems.

onliner said:
This.
I always install roms with the procedure i said above and have never had any problems.
Click to expand...
Click to collapse
Alright so got one doubt, I used OOS 10.3.2 to flash, should it be oos 10.0 only?
Thought that didn't make a difference.

I am also facing the same issue. Were you able to find any solution ?

So I found out treskmod omni rom and Paranoid android quartz 2 work perfectly , try those out, it still doesn't solve the problem in the other roms though. So not exactly a solution.