Database Users

[Q] Many Advanced Questions Regarding ROMs

I am getting into development more and have a new load of questions. And yes, I searched first.
Do all Roms include firmware(OS), kernal, baseband, and boot loader?
Do over-the-air updates include the baseband and boot loader, or only the kernal and firmware/(OS).
I once used the Wugfreth toolkit to reinstall the stock ROM. It flashed the baseband with the same version and then attempted to flash the boot loader with the same version, but failed. How can I JUST flash the kernal and firmware/os.
This may be dumb question, but what language is the boot loader and baseband written in? Is it encrypted, or can anyone edit it and flash?
What happens if the boot loader, baseband, kernal, and firmware versions do not match?
I did not know the ROM included the bootloader, and I almost purposely flash the ROM of another device to see what would happen, figuring I could have restored using fastboot. But that probably would have hard-bricked it, right? I thought flashing a ROM was completely safe because it did not touch the boot loader, and could always be undone with fastboot?
How do you developers test out modified bootloaders without making a simple coding mistake and ruining your device?
How can you flash a bootloader using itself (fastboot)?
I saw a post for a different device for changing the boot loader logo. Not the firmware's boot animation. I don't want mine to say "Google" with an unlock icon. Can this be done on the Nexus 7?
I read the partition sizes are determined by the boot loader, and not adjustable. Is this correct? I am running stock 4.4.3 and only have 11MB free on the system partition. How do custom Roms fit within this limit? I am worried this will prevent a custom ROM based in 5.0 Lollipop, and the Nexus 7 2012 will be stuck on Kitkat. Maybe the firmware could be loaded on the data partition with a symbolic link to the system partition?
Thank you

I'm not a developer, but can answer some of your questions (at least as they relate specifically to the Nexus 7).
Custom ROMS typically just include the firmware/kernel (and i believe the radio/baseband if it's for a 3g/mobile device, though these can also be flashed separately, and i could be wrong on this part.) Bootloader is typically untouched, but this might differ on other devices.
As for OTA updates and what all they include, well that depends on the device, manufacturer, carrier, and even the specific OTA. It could potentially include everything (firmware/kernel updates, bootloader, radio/baseband, etc.), but may be any combination of the different components.
Available free space on the system partition doesn't really matter if you're flashing a new ROM, because you'll be wiping the partition as part of the flashing process. ROMs typically don't include GAPPS either (unless it's just a modified version of stock), so will actually take up much less room than the stock ROM on their own. Then you can decide which GAPPS to flash separately, there are various packages available in different sizes; some just include the basic google play services needed to have the play store and related basic functionality, others will mirror the stock pre-installed apps.
If you're using a custom recovery to flash a ROM, they typically contain a script to first verify the device matches, if not, it won't even flash. If you do manage to flash an incompatible ROM (via fastboot maybe, or if it doesn't include a verification script), with a Nexus this typically is not a big deal, you just won't ever actually boot into the ROM, but should still be able to boot into recovery or bootloader and then flash a compatible ROM.
If you flash an incompatible kernel on top of a ROM, you'll likely get a bootloop/softbricked device.
Flashing an incompatible bootloader may brick the device. Any tinkering with the bootloader is always risky.
Hope that helps a little, I'll take another look when I'm not at work

flyoffacliff said:
I am getting into development more and have a new load of questions. And yes, I searched first.
Do all Roms include firmware(OS), kernal, baseband, and boot loader?
Do over-the-air updates include the baseband and boot loader, or only the kernal and firmware/(OS).
I once used the Wugfreth toolkit to reinstall the stock ROM. It flashed the baseband with the same version and then attempted to flash the boot loader with the same version, but failed. How can I JUST flash the kernal and firmware/os.
This may be dumb question, but what language is the boot loader and baseband written in? Is it encrypted, or can anyone edit it and flash?
What happens if the boot loader, baseband, kernal, and firmware versions do not match?
I did not know the ROM included the bootloader, and I almost purposely flash the ROM of another device to see what would happen, figuring I could have restored using fastboot. But that probably would have hard-bricked it, right? I thought flashing a ROM was completely safe because it did not touch the boot loader, and could always be undone with fastboot?
How do you developers test out modified bootloaders without making a simple coding mistake and ruining your device?
How can you flash a bootloader using itself (fastboot)?
I saw a post for a different device for changing the boot loader logo. Not the firmware's boot animation. I don't want mine to say "Google" with an unlock icon. Can this be done on the Nexus 7?
I read the partition sizes are determined by the boot loader, and not adjustable. Is this correct? I am running stock 4.4.3 and only have 11MB free on the system partition. How do custom Roms fit within this limit? I am worried this will prevent a custom ROM based in 5.0 Lollipop, and the Nexus 7 2012 will be stuck on Kitkat. Maybe the firmware could be loaded on the data partition with a symbolic link to the system partition?
Thank you
Click to expand...
Click to collapse
1. roms dont include a bootloader.
2. no
3. easily in a custom recovery.
4. i have no idea, and its the most secure part of the device.
5. nothing.
6. roms DO NOT EVER include bootloaders.
7. developers on nexus devices never modify the bootloader. first off, its extremely tedious and difficult. secondly, there is no need, as our bootloaders are unlockable and lockable.
8. it overwrites itself, but you are on your computer using fastboot, phone is just plugged into it.
9. no.
10. each partition has its own size. roms go into a partition that also holds your storage, and is separated from the storage. another reason why you dont have 16gb storage when you buy a 16gb device, because some of it gets allocated to the system.

XT-1644 Official Nougat Update?

My Phone Info:
Single sim 2gb ram + 16gb rom
Hello folks I've been searching for a nougat update for XT-1644, but unable to find over the xda if anyone of you havs upgraded your xt-1644 then kindly tell the procedure here, Thanks.
Here is my About Phone Info.
http://cloud.tapatalk.com/s/589c8f61b2eab/Screenshot_20170209-203359.png
http://cloud.tapatalk.com/s/589c8f48b01b2/Screenshot_20170209-203401.png

You mean a method like this? https://forum.xda-developers.com/moto-g4-plus/how-to/xt1644-stock-marshmallow-to-nougat-t3540022
If you download the 93-14 Nougat firmware, that's the latest version. Nougat OTAs currently only exist for the 93-11 firmware.

echo92 said:
You mean a method like this? https://forum.xda-developers.com/moto-g4-plus/how-to/xt1644-stock-marshmallow-to-nougat-t3540022
If you download the 93-14 Nougat firmware, that's the latest version. Nougat OTAs currently only exist for the 93-11 firmware.
Click to expand...
Click to collapse
Sorry didn't find that,
One more question i have unlocked my bootloader will it work? I mean will i be able to flash this 7.0?

waseemmayaa said:
Sorry didn't find that,
One more question i have unlocked my bootloader will it work? I mean will i be able to flash this 7.0?
Click to expand...
Click to collapse
Yes, your bootloader status won't matter - as long as that's all you've done. As I understand it, the update via stock recovery only cares if the rest of your phone has been modified - if you've still got a stock bootloader, stock recovery and stock kernel (from MM, provided it's up to date), it should work and you should be eligible for future OTAs.
The only hurdle I could see happening is that the build of Marshmallow expected by the OTA and your phone's current OS build do not match, in which case it won't install. Thus, you may have to consult one of the fastboot Nougat 93-11 or 93-14 threads to install, which you'll have to do if your system is modified past the bootloader.
Here are a couple for your perusal:
https://forum.xda-developers.com/moto-g4-plus/how-to/moto-g4-plus-xt1640-43-athene-npj25-93-t3549369
https://forum.xda-developers.com/moto-g4-plus/how-to/android-7-0-install-nougat-official-t3531612

echo92 said:
Yes, your bootloader status won't matter - as long as that's all you've done. As I understand it, the update via stock recovery only cares if the rest of your phone has been modified - if you've still got a stock bootloader, stock recovery and stock kernel (from MM, provided it's up to date), it should work and you should be eligible for future OTAs.
The only hurdle I could see happening is that the build of Marshmallow expected by the OTA and your phone's current OS build do not match, in which case it won't install. Thus, you may have to consult one of the fastboot Nougat 93-11 or 93-14 threads to install, which you'll have to do if your system is modified past the bootloader.
Here are a couple for your perusal:
https://forum.xda-developers.com/moto-g4-plus/how-to/moto-g4-plus-xt1640-43-athene-npj25-93-t3549369
https://forum.xda-developers.com/moto-g4-plus/how-to/android-7-0-install-nougat-official-t3531612
Click to expand...
Click to collapse
Thanks for the brief info, it means i have to flash it via fastboot and if that works fine then I'll be able to get OTA, but for your info, I've unlocked bootloader and installed Official TWRP but if i flash any of the firmware (given above) will i face bootloop kinda stuffs? I am scared if something goes wrong then i will even not able to restore nandroid backup. Hope you gotta help me.
Thanks.

waseemmayaa said:
Thanks for the brief info, it means i have to flash it via fastboot and if that works fine then I'll be able to get OTA, but for your info, I've unlocked bootloader and installed Official TWRP but if i flash any of the firmware (given above) will i face bootloop kinda stuffs? I am scared if something goes wrong then i will even not able to restore nandroid backup. Hope you gotta help me.
Thanks.
Click to expand...
Click to collapse
I see you've received a response in the other thread regarding if XT1644 will accept the update; given you've flashed TWRP, if you wish to be very safe, I would suggest re-installing your Marshmallow ROM so you have a stock install before proceeding to Nougat. There's nothing stopping you from directly flashing Nougat, and the fastboot method for either Nougat build may correctly overwrite the relevant files, the only way is to try the procedure. Don't use the TWRP backup images of Nougat - they don't contain updates to your baseband modem and other core parts of your device - they are only meant to be used once your entire phone is updated to Nougat.
If you wish to restore back to stock MM before flashing Nougat, here's links to stock firmware for XT1644: https://forum.xda-developers.com/moto-g4-plus/how-to/xt1644-firmware-t3454980
But either way, read all the instructions first, ensure you've got all the firmware and tools you need installed/downloaded, your phone has at least 50 % battery and plenty of time, and you should be okay.

Bootloader and other questions.

Hello all.
Im a little bit confused about the bootloaders and their marriage with their standard ROMS.
I am in MM B13 in a 2017 unlocked using bkores toolkit and would like to check Nougat ROMS.
What happens if, from this MM unlocked state I flash an official Nougat for 2017? Is safe? Could I eventually flash a TWR to return to my "original and safe" state? Could I flash back an "official" MM B13 for example?
I am guessing that maintaining the phone in the unclocked area is safer than recover the lock. Is this true?
There is a "Universal bootloader" for Nougat ROMS. How "Universal" is this bootloader? Does this bootloader runs in MM?.
If I apply a SD "complete" update (being MM B13 or Nougat), do I relock the phone's bootloader?
If I upgrade fro MM to N, do I lost the possibility of flashing a custom recovery? (TWRP). This is a non go for me, as you cannot go back...
Hope you can answer these questions
Regards

jrotaetxe said:
Hello all.
Im a little bit confused about the bootloaders and their marriage with their standard ROMS.
I am in MM B13 in a 2017 unlocked using bkores toolkit and would like to check Nougat ROMS.
What happens if, from this MM unlocked state I flash an official Nougat for 2017? Is safe? Could I eventually flash a TWR to return to my "original and safe" state? Could I flash back an "official" MM B13 for example?
I am guessing that maintaining the phone in the unclocked area is safer than recover the lock. Is this true?
There is a "Universal bootloader" for Nougat ROMS. How "Universal" is this bootloader? Does this bootloader runs in MM?.
If I apply a SD "complete" update (being MM B13 or Nougat), do I relock the phone's bootloader?
If I upgrade fro MM to N, do I lost the possibility of flashing a custom recovery? (TWRP). This is a non go for me, as you cannot go back...
Hope you can answer these questions
Regards
Click to expand...
Click to collapse
Forget about the bootloader thing for now - it should be universal for MM and N. Not gonna relock itself.
-If you want to go back from a custom ROM (you'd have the A2017X_Universal_Bootloader, the ROM and the modem that goes with your device, plus a version of TWRP installed) what you would do, at least in A2017Gs and Us, is to flash a stock recovery zip to get the stock recovery. After that you reboot to the recovery, and you'll get to MiFavor's recovery. from there you would flash an official zip and every partition would be overwritten with what's on the zip. I suspect that ZTE packs every update with everything in it so that you can roll back, say, from Nougat to Marshmallow officialy, without messing everything up.
OR you can use MiFlash to reflash everything with a computer. Just download the full EDL file from 4PDA and flash, you'll get full stock (but still unlocked BL anyways)
So yeah, you CAN get back to full stock anytime.
-Don't just try to relock the bootloader. AFAIK if you relock it and you have root or TWRP or somesuch you can brick your device. I'd advise against trying to do that, but if you must, look at a guide or two at least.
-Yeah, pretty universal. I wonder why you'd want a custom MM ROM though. if you want to go back to stock MM it will get replaced by another one anyways.
-Already addressed, no
-I don't know the exact case with A2017 phones, but you said you cannot go back? You can. If you're on official N and want to roll back all you have to do is put an official MM zip on your SD or internal storage and go to Updates.
That being said, you still can use axon7tool on Nougat if it supports A2017 phones, which it should. You use EDL mode to flash the recovery. it is what I always do on my A2017G.

Choose an username... said:
Forget about the bootloader thing for now - it should be universal for MM and N. Not gonna relock itself.
....
Click to expand...
Click to collapse
So...
i) Bootloader unlocked is safer than locked and problems can arise if i try to relock.
ii) I can flash from SD every official thing published by ZTE if I flash previously ZTE recovery. (bootloader still unlocked). From that startpoint, I could reflash TWRP using fastboot or EDL. Once in TWRP, every ROM is flashable if partition compatible...
iii) I can stay with my unlocked bootloader with every MM or N. Important things are the modem and other stuff. N is not much different from MM and I like Xposed....
Big, big THANK YOU!!!!

jrotaetxe said:
So...
i) Bootloader unlocked is safer than locked and problems can arise if i try to relock.
ii) I can flash from SD every official thing published by ZTE if I flash previously ZTE recovery. (bootloader still unlocked). From that startpoint, I could reflash TWRP using fastboot or EDL. Once in TWRP, every ROM is flashable if partition compatible...
iii) I can stay with my unlocked bootloader with every MM or N. Important things are the modem and other stuff. N is not much different from MM and I like Xposed....
Big, big THANK YOU!!!!
Click to expand...
Click to collapse
i)Yeah
ii)Every LOS-based ROM is flashable if you flash the Universal Bootloader and the corresponding modem for your device, except stock roms and maybe stock-based roms (not sure)
iii)Yeah

Thank you again, my annonimous friend.

LineageOS on a vzw Galaxy S5?

Can I put LineageOS on my Galaxy S5 using SafeStrap? If not, would Odin do the trick instead?
What, if anything, do I need to do to maintain root?
Do I need to unlock the bootloader before flashing the ROM?
Do the steps in the above link work on unlocking the verizon bootloader or will I make a brick?
If there's a link to getting LineageOS onto my Verizon S5 while keeping root please point me in the right direction. Thank you.

androidman807 said:
Can I put LineageOS on my Galaxy S5 using SafeStrap? If not, would Odin do the trick instead?
What, if anything, do I need to do to maintain root?
Do I need to unlock the bootloader before flashing the ROM?
Do the steps in the above link work on unlocking the verizon bootloader or will I make a brick?
If there's a link to getting LineageOS onto my Verizon S5 while keeping root please point me in the right direction. Thank you.
Click to expand...
Click to collapse
you first need to root then unlock bootloader then install twrp then flash Lineage and Gapps and your all set , all information regarding how to root and unlock bootloader are in the vzw section , do make a full back up of your sdcard(micro sd card) to your computer because unlocking the bootloader will wipe/format your memory card(keep that in mind)
also i suggest you update your modem and bootloader , just in case you would like to test the ported rom which most of them run on a higher bootloader and with a old bootloader you will face issues with wifi and nav buttons specially with the vzw variant (i also have a vzw) , update it to i think the highest so far by @jrkruze is qf2 , for example the skiesrom (a s8 port) runs on a qf5 bootloader but updating vzw bootloader to qf2 fixes the wifi and nav button bugs.
Good Luck and also do properly read the instructions word for word.

I'm so grateful for your response. You've been down this road and know the traps. I believe my original post has the right thread on unlocking the bootloader for vzw, and I appreciate the warning about it erasing the micro-sd card.
Two follow-up questions:
Where can I find the update for the modem?
Also to avoid the wifi and nav problems, do I want the QF2 or QF5? And where do I find those? Here it says to use latest bootloader (QA1) with QF2 modem. Does that make sense? If so I just need to know where to find those.
Thank you again so very much.
KazuDante said:
you first need to root then unlock bootloader then install twrp then flash Lineage and Gapps and your all set , all information regarding how to root and unlock bootloader are in the vzw section , do make a full back up of your sdcard(micro sd card) to your computer because unlocking the bootloader will wipe/format your memory card(keep that in mind)
also i suggest you update your modem and bootloader , just in case you would like to test the ported rom which most of them run on a higher bootloader and with a old bootloader you will face issues with wifi and nav buttons specially with the vzw variant (i also have a vzw) , update it to i think the highest so far by @jrkruze is qf2 , for example the skiesrom (a s8 port) runs on a qf5 bootloader but updating vzw bootloader to qf2 fixes the wifi and nav button bugs.
Good Luck and also do properly read the instructions word for word.
Click to expand...
Click to collapse

androidman807 said:
I'm so grateful for your response. You've been down this road and know the traps. I believe my original post has the right thread on unlocking the bootloader for vzw, and I appreciate the warning about it erasing the micro-sd card.
Two follow-up questions:
Where can I find the update for the modem?
Also to avoid the wifi and nav problems, do I want the QF2 or QF5? And where do I find those? Here it says to use latest bootloader (QA1) with QF2 modem. Does that make sense? If so I just need to know where to find those.
Thank you again so very much.
Click to expand...
Click to collapse
The Latest bootloader (after you unlocked your current bootloader) : https://forum.xda-developers.com/showpost.php?p=73734257&postcount=3143
latest modem : https://forum.xda-developers.com/showpost.php?p=61802396&postcount=1 ( use the ones in the odin section , you will need to be bootloader unlocked and have odin+latest samsung drivers installed)
latest twrp : https://dl.twrp.me/klte/ ( the ones that ends with .tar are for flashing using odin , since you dont have twrp yet but flashing twtp comes last after rooting and unlocking bootloader and updating bootloader then update the modem then odin flash twrp then have lineageos and nougat gapps on memory card. reboot while holding vol up and home button to reboot into twrp to install lineageos system then gopengapps , afterwards you can install magisk to have root access on lineageOS as well .
p.s after you unlock bootloader and the system reboots normally return to download mode then use odin to flash twrp , i just noticed(remembered that latest bootloader update uses twrp and not safestrap recovery.
to unlock current bootloader : https://forum.xda-developers.com/showpost.php?p=71202995&postcount=3

Thank you so much. So if I understand right it's:
1) UNLOCK bootloader
2) UPDATE bootloader (latest is QF2)
3) update modem (latest tar was QI2)
4) flash TWRP from Odin (you linked to klte version; qualcomm but I have vzw)
5) install LineageOS and gapps from TWRP
6) install magisk from TWRP to get root
Is that correct?
Correct bootloader and modem versions?
OK to use klte for Verizon?
Magisk is for root, done last, and not superSu?
If all those are Yes, then I guess the prep work is done and now I just have to bite the bullet, do a safestrap and titanium backup and dive in.
Thanks again - I really do appreciate it.
KazuDante said:
The Latest bootloader (after you unlocked your current bootloader) : https://forum.xda-developers.com/showpost.php?p=73734257&postcount=3143
latest modem : https://forum.xda-developers.com/showpost.php?p=61802396&postcount=1 ( use the ones in the odin section , you will need to be bootloader unlocked and have odin+latest samsung drivers installed)
latest twrp : https://dl.twrp.me/klte/ ( the ones that ends with .tar are for flashing using odin , since you dont have twrp yet but flashing twtp comes last after rooting and unlocking bootloader and updating bootloader then update the modem then odin flash twrp then have lineageos and nougat gapps on memory card. reboot while holding vol up and home button to reboot into twrp to install lineageos system then gopengapps , afterwards you can install magisk to have root access on lineageOS as well .
p.s after you unlock bootloader and the system reboots normally return to download mode then use odin to flash twrp , i just noticed(remembered that latest bootloader update uses twrp and not safestrap recovery.
to unlock current bootloader : https://forum.xda-developers.com/showpost.php?p=71202995&postcount=3
Click to expand...
Click to collapse

androidman807 said:
Thank you so much. So if I understand right it's:
1) UNLOCK bootloader
2) UPDATE bootloader (latest is QF2)
3) update modem (latest tar was QI2)
4) flash TWRP from Odin (you linked to klte version; qualcomm but I have vzw)
5) install LineageOS and gapps from TWRP
6) install magisk from TWRP to get root
Is that correct?
Correct bootloader and modem versions?
OK to use klte for Verizon?
Magisk is for root, done last, and not superSu?
If all those are Yes, then I guess the prep work is done and now I just have to bite the bullet, do a safestrap and titanium backup and dive in.
Thanks again - I really do appreciate it.
Click to expand...
Click to collapse
yes thats correct , also there is no vzw variant of lineage since vzw is merged under klte , so every rom you download the one you have to choose is klte unless the dev make a build for each variant but not likely to happen anymore.

A very basic assumption may have been overlooked, but it seems the CID on my lollipop PB1 is 11 Toshiba eMMC. Method 2 of unlocking stopped at step 4 with an error in the terminal screen indicating this is only for Samsung eMMCs. Is it possible to unlock an 11, and if so, where would I find those steps?
KazuDante said:
yes thats correct , also there is no vzw variant of lineage since vzw is merged under klte , so every rom you download the one you have to choose is klte unless the dev make a build for each variant but not likely to happen anymore.
Click to expand...
Click to collapse

androidman807 said:
A very basic assumption may have been overlooked, but it seems the CID on my lollipop PB1 is 11 Toshiba eMMC. Method 2 of unlocking stopped at step 4 with an error in the terminal screen indicating this is only for Samsung eMMCs. Is it possible to unlock an 11, and if so, where would I find those steps?
Click to expand...
Click to collapse
sadly cid 11 cannot be unlocked , best option is to only change current S5 with another S5 and hope its a CID 15 , or sadly get another phone but check xda forum to see if it has any latest custom roms and bootloader can be unlocked.
But for CID 11 theres no unlocks for those , only thing is safestrap roms that allows you to run ports like PhoenixRom and other stock but modded roms but using safestrap

Thanks you so much again. How can I tell which ROMs are stock I can use in safestrap (like Phoenixrom) and which are custom I can't use (like LineageOS)?
And if I have a safestrap backup to my sd card of my stock lollipop and don't like phoenix (which seems to be MM) can I restore from safestrap back to my stock LL?
KazuDante said:
sadly cid 11 cannot be unlocked , best option is to only change current S5 with another S5 and hope its a CID 15 , or sadly get another phone but check xda forum to see if it has any latest custom roms and bootloader can be unlocked.
But for CID 11 theres no unlocks for those , only thing is safestrap roms that allows you to run ports like PhoenixRom and other stock but modded roms but using safestrap
Click to expand...
Click to collapse

androidman807 said:
Thanks you so much again. How can I tell which ROMs are stock I can use in safestrap (like Phoenixrom) and which are custom I can't use (like LineageOS)?
And if I have a safestrap backup to my sd card of my stock lollipop and don't like phoenix (which seems to be MM) can I restore from safestrap back to my stock LL?
Click to expand...
Click to collapse
that im not sure about that so i cant give you any pointers since i have not done anything with safestrap besides the process to unlock the bootloader.

Thanks anyway. It seems it should work, since safestrap won't disappear. Maybe I should post a new thread. Thank you again for all your time.
KazuDante said:
that im not sure about that so i cant give you any pointers since i have not done anything with safestrap besides the process to unlock the bootloader.
Click to expand...
Click to collapse

I am also essentially looking to install LineageOS on my Galaxy S5, but before proceeding, I just wanted to make sure that what I'm looking to do is correct. Currently I am running an old version of PhoenixROM with an old unlocked bootloader. I know that I will need to update the bootloader in order to prevent issues, such as wifi not working.
Should all I need to do is follow JKruse's instructions here, flashing LineageOS as the last and final step? I'm hoping that it is this easy, but I do have my doubts and that is why I am asking on here for advice.
Thank you to all in advance!

[Guide] Convert to Global [WIP]

*** Use this at your very own risk.
***Backup your persist.img. There is a guide to fix it if needed.
*** Backup your working modem. Sometimes it is as simple as restoring it if you lose signal.
*** When flashing, you must understand the difference between fastboot and fastbootd to avoid flashing errors.
*** Backup your files in a safe place.
*** Some users are reporting that the whole thing is not working and going on a blame streak. So if you're not quite ready, please don't attempt this.
Basic Instructions: "I will test again since some users are losing signal after flashing". There is a debate whether msm and update the tmobile firmware, or flash the global. Again this is a WIP.
MSM. Here is the thread.
Unlock bootloader or re-unlock bootloader ... Enable OEM Unlock in developer options. flash token.
Fastboot
Code:
fastboot flash cust-unlock <unlock_token.bin>
Code:
fastboot oem unlock
and now your bootloader is unlocked.
Here is the t-mobile article for the 6t. same instructions for the 8 if you're new to this.
NEXT:
Link to fastboot thread
https://forum.xda-developers.com/oneplus-8/how-to/rom-stock-fastboot-roms-oneplus-8-t4084629
Download the global fastboot rom from here.
Unzip and flash all.
Link to twrp thread:
https://forum.xda-developers.com/oneplus-8/development/recovery-unofficial-twrp-oneplus-8-t4101315
If you want to root.
Boot into twrp or flash the twrp installer. TWRP 3.3.1-10 Test by mauronofrio and or TWRP 3.3.1-10 Test Installer by mauronofrio "newer ones may work"
After booting, you can flash magisk with-in twrp and you're rooted.
I have used oxygen updater to update the firmware while rooted. After the local install, open magisk and flash on the inactive slot.
---------------
If you ever want to revert, use the msm tool. Here is the thread.
https://forum.xda-developers.com/oneplus-8/how-to/op8-unbrick-tool-to-restore-device-to-t4093043
---------
Old information from the old thread is below, if you want to use it only for reference or for backing up the FP persist
---------------
Old Instructions
Here we go .....
This is fairly new and hasn't been tested so, proceed with caution. There are more knowledgable people here. This was just tested quick and it worked.
Requirements
1-Be on T-mobile firmware and update to the latest version. If you are bootloader unlocked, you mean not be able to take OTA's and you may need to reflash with MSM and update, then unlock the bootloader again. Thread Thanks @Some_Random_Username
2 - Unlock your bootloader.
3- --! IMPORTANT: Make a TWRP backup of your MODEM because we'll restore that later, why? because t-mobile sim doesn't work on the Global Modem. You can also back everything up in TWRP just in case.
If you have OTG, make the backup there so it is safe. You can restore the modem through TWRP with the OTG.
4-Backup your persist. Otherwise you may lose the fingerprint.
You'll need root.
Code:
adb shell
HTML:
su
Code:
dd if=/dev/block/bootdevice/by-name/persist of=/sdcard/persist.img
Then
Code:
adb pull sdcard/persist.img
Then copy it from from Sdcard to a safe place
*** You may lose signal again if you update the global version. It is a WIP but keep your modem backed up!
With all the above:
It is simple. Download the global firmware and flash it through fastboot. Here is the thread
.. I tested with "10.5.5-GLOBAL-OnePlus8Oxygen_15.O.14" Thanks @mauronofrio
Reboot to fastboot
Unzip and flash-all
It will reboot to the global firmware. "Now you won't get cellphone signal"
Skip the setup and reboot to fastboot.
reboot to twrp, do not flash it.
Code:
fastboot boot twrp.img
link to twrp thread. . I used TWRP 3.3.1-2 Test by @mauronofrio
plug in the OTG or locate the backup and Restore the Modem" to get signal
Reboot and you'll have signal.
To root. you can flash the patched boot located in the sourceforge folder " Patched-Stock-Boot" on this thread
Code:
fastboot flash boot filename.img
You can also flash magisk in twrp. I prefer the patched boot.
Bonus: I am running the Nolimit magisk rom Thanks @xXx
https://forum.xda-developers.com/on...gisk-rom-xxx-nolimits-11-0-speed-ram-t4088609
Thanks @Some_Ghost for testing.

B-E-A-UTIFUL!
I'll wait to see others' results before I brick my phone.

rjp0615 said:
B-E-A-UTIFUL!
I'll wait to see others' results before I brick my phone.
Click to expand...
Click to collapse
It works no bricking. If something happened you can go back with MSM.

matteosaeed said:
Here we go .....
This is fairly new and hasn't been tested so, proceed with caution. There are more knowledgable people here. This was just tested quick and it worked.
Requirements
1-Be on T-mobile firmware and update to the latest version. If you are bootloader unlocked, you mean not be able to take OTA's and you may need to reflash with MSM and update, then unlock the bootloader again. Thread Thanks @Some_Random_Username
2 - Unlock your bootloader.
3- --! IMPORTANT: Make a TWRP backup of your MODEM because we'll restore that later, why? because t-mobile sim doesn't work on the Global Modem. You can also back everything up in TWRP just in case.
If you have OTG, make the backup there so it is safe. You can restore the modem through TWRP with the OTG.
4-Backup your persist. Otherwise you may lose the fingerprint.
*** You may lose signal again if you update the global version. It is a WIP but keep your modem backed up!
With all the above:
It is simple. Download the global firmware and flash it through fastboot. Here is the thread
.. I tested with "10.5.5-GLOBAL-OnePlus8Oxygen_15.O.14" Thanks @mauronofrio
Reboot to fastboot
Unzip and flash-all
It will reboot to the global firmware. "Now you won't get cellphone signal"
Skip the setup and reboot to fastboot.
reboot to twrp, do not flash it.
Code:
fastboot boot twrp.img
link to twrp thread. . I used TWRP 3.3.1-2 Test by @mauronofrio
plug in the OTG or locate the backup and Restore the Modem" to get signal
Reboot and you'll have signal.
To root. you can flash the patched boot located in the sourceforge folder " Patched-Stock-Boot" on this thread
Code:
fastboot flash boot filename.img
You can also flash magisk in twrp. I prefer the patched boot.
Bonus: I am running the Nolimit magisk rom Thanks @xXx
https://forum.xda-developers.com/on...gisk-rom-xxx-nolimits-11-0-speed-ram-t4088609
Thanks @Some_Ghost for testing.
Click to expand...
Click to collapse
Am I understanding correctly, we will have to re-flash the modem after EVERY update?

rjp0615 said:
Am I understanding correctly, we will have to re-flash the modem after EVERY update?
Click to expand...
Click to collapse
For the global, we don't know until we get it, but @Some_Ghost checked with the euro and signal stays, so you can do the euro version instead of the global and still keep the the signal without reflashing your modem.

Does anybody have the modem backup I lost mine and can't find fastboot for tmobile

The EU modem dont fix it I just need tmobile modem if anyone can can someone give be the modem either tarp backup or .img file so I can use data

very easy fix for modem get the ota after you flash global you do ota and modem works fastboot wont flash modem right

delete
---------- Post added at 02:38 AM ---------- Previous post was at 02:32 AM ----------
ecompton59 said:
The EU modem dont fix it I just need tmobile modem if anyone can can someone give be the modem either tarp backup or .img file so I can use data
Click to expand...
Click to collapse
If you flash your modem backup with Euro firm it sticks throughout updates so far... It didn't work for me on global. You still need to restore your modem backup on either firmwares. Global so far modem doesn't stick after updates, euro so far, it stays after updates.

Some_Ghost said:
delete
---------- Post added at 02:38 AM ---------- Previous post was at 02:32 AM ----------
If you flash your modem backup with Euro firm it sticks throughout updates so far... It didn't work for me on global. You still need to restore your modem backup on either firmwares. Global so far modem doesn't stick after updates, euro so far, it stays after updates.
Click to expand...
Click to collapse
I fixed it with ota if you flash global do the enable and and dev settings I waited to install magisk. Ayer first boot put ota for global and it works because ota has modem in it and fastboot can't flash modem yet with bat file but I have no issues I have global modem and global ROM and from here on ota will work no need for modem

not really converting to Global then? this is just so you can use dev ROM, but since DEV rom hasnt come about there really is no reason to do this.

Vio281 said:
not really converting to Global then? this is just so you can use dev ROM, but since DEV rom hasnt come about there really is no reason to do this.
Click to expand...
Click to collapse
What? He used global ROM. Not a DEV ROM.

ecompton59 said:
I fixed it with ota if you flash global do the enable and and dev settings I waited to install magisk. Ayer first boot put ota for global and it works because ota has modem in it and fastboot can't flash modem yet with bat file but I have no issues I have global modem and global ROM and from here on ota will work no need for modem
Click to expand...
Click to collapse
I will try this thanks ??

Does the Global ROM share the same 5G compatibility introduced in the new TMO ROM?

joemossjr said:
What? He used global ROM. Not a DEV ROM.
Click to expand...
Click to collapse
Thats what I'm saying, this is to flash rom, it not necessarily converting the phone to a global phone since it still need Tmobile Modem bin file in order to be function as a phone. If you take the phone outside the U.S it questionable if it works, that is why I say this is only for Dev Rom and in this case stock global rom but it is not a global phone.

@joemossjr
Vio281 said:
Thats what I'm saying, this is to flash rom, it not necessarily converting the phone to a global phone since it still need Tmobile Modem bin file in order to be function as a phone. If you take the phone outside the U.S it questionable if it works, that is why I say this is only for Dev Rom and in this case stock global rom but it is not a global phone.
Click to expand...
Click to collapse
Well check @ecompton59 's response. He was able to get things working.
The modem does work, just there is an issue with the fastboot flashing the modems. The TWRP restore of the modem is to get cell signal right away.
Here is what I did:
After I did what is in the first post in the thread:
I used oxygen updater to download the EU update and flashed it via "Local Upgrade" @Some_Ghost tested that as well.
There is signal. I believe that it may have flashed the modem "maybe", unlike fastboot.
While I was on the EU version, I downloaded the update for the global, and did a "Local Upgrade" again, and got signal.
I did all of this with Magisk being installed and after each "local upgrade, before reboot" I install Magisk on the "inactive slot, ota".
Technically speaking and don't quote me 100%, the first flash to the global is what gives issues with the sim, but that's the way to get the ability to do "local upgrade" because it is disabled on the t-mobile firmware.
Theoretically and I haven't tested.
Unlock bootloader >> Flash global "won't flash everything properly" = no signal
Global to another global or EU update >> will flash the modem >> signal will work "as it will properly flash everything"

matteosaeed said:
@joemossjr
Well check @ecompton59 's response. He was able to get things working.
The modem does work, just there is an issue with the fastboot flashing the modems. The TWRP restore of the modem is to get cell signal right away.
Here is what I did:
After I did what is in the first post in the thread:
I used oxygen updater to download the EU update and flashed it via "Local Upgrade" @Some_Ghost tested that as well.
There is signal. I believe that it may have flashed the modem "maybe", unlike fastboot.
While I was on the EU version, I downloaded the update for the global, and did a "Local Upgrade" again, and got signal.
I did all of this with Magisk being installed and after each "local upgrade, before reboot" I install Magisk on the "inactive slot, ota".
Technically speaking and don't quote me 100%, the first flash to the global is what gives issues with the sim, but that's the way to get the ability to do "local upgrade" because it is disabled on the t-mobile firmware.
Theoretically and I haven't tested.
Unlock bootloader >> Flash global "won't flash everything properly" = no signal
Global to another global or EU update >> will flash the modem >> signal will work "as it will properly flash everything"
Click to expand...
Click to collapse
again, this does not make it a global sim unlock phone, you are flashing a previous Tmobile Modem on top of a Global rom.

Vio281 said:
again, this does not make it a global sim unlock phone, you are flashing a previous Tmobile Modem on top of a Global rom.
Click to expand...
Click to collapse
It at least we can run different firmwares on T-Mobile. You could try the global msm on T-Mobile and report back. As being sim unlocked depends on the bands enabled in other countries but should work with any sim.

matteosaeed said:
It at least we can run different firmwares on T-Mobile. You could try the global msm on T-Mobile and report back. As being sim unlocked depends on the bands enabled in other countries but should work with any sim.
Click to expand...
Click to collapse
is there different functionality between the tmobile modem and global modem firmware? I flashed the global rom and am using that with tmobile modem flashed through twrp. I haven't done a local update yet to get the global modem. if I do, what is the difference running that vs the tmobile modem? im in seattle using tmobile anyway.... would I see a difference in anything? speed? I had updated to the tmobile ota right before I flashed, they supposedly updated something with the modem in that update. im just wondering if there is a benefit to using the global modem or not. I definitely see the benefit in using he global rom though....lol

bluemoel said:
is there different functionality between the tmobile modem and global modem firmware? I flashed the global rom and am using that with tmobile modem flashed through twrp. I haven't done a local update yet to get the global modem. if I do, what is the difference running that vs the tmobile modem? im in seattle using tmobile anyway.... would I see a difference in anything? speed? I had updated to the tmobile ota right before I flashed, they supposedly updated something with the modem in that update. im just wondering if there is a benefit to using the global modem or not. I definitely see the benefit in using he global rom though....lol
Click to expand...
Click to collapse
you'll be fine, my signal hasn't changed since flashing it remained the same as far as I can tell
---------- Post added at 12:34 PM ---------- Previous post was at 12:30 PM ----------
Vio281 said:
again, this does not make it a global sim unlock phone, you are flashing a previous Tmobile Modem on top of a Global rom.
Click to expand...
Click to collapse
Be happy that people actually take the time to experiment and work on things like this for the community so we can root and run different firmwares, kernels, and recoveries etc. At the least we aren't stuck on TMO firmware with lack of updates and missing features and as far as we can tell everything is working and odds are you aren't going to be using a T-Mobile SIM when going out of country anyway. Any issues will be ironed out when we cross that path I am sure ??