Database Users

Please Point Me to The Right Direction

Hello the Wonderful and Fantastic Members of the XDA Community,
I'm in the process of researching on how to unlock bootloader, install magix and ultimately root the phone, and I hope that someone can point me to the right guides to accomplish these steps. I have been trying to figure it out but would feel much better if someone can point me to the right guide as opposed to me blindly guessing which guide I should follow. This is what I know so far:
1. I believe that in order to use Magix, I need to have a "Custom Recovery" which requires I unlock phone's "bootloader". But before I can do that, I need to have a stock system, which DrakenFX had gracious posted but I'm not too sure how to find. Can someone point me to the right forum to obtain the stock system image from DrakenFX and the guide to unlocking the bootloader for this phone? What are some precautions I should take prior to attempting to unlock the bootloader? And what do I need to do with the stock system if everything goes south with my attempt? I'm currently on A2017UV1.0.0B27 (after the latest update). Will the stock system work with that?
2. I believe that after I unlock the bootloader, I have to install the Custom Recovery, which I think I should use TWRP - is it compatible with magix? After I install TWRP, I need to use TWRP to "flash" magix onto my phone? How can I install TWRP and use it to flash magix? What are some of the precautions I need to take before my attempt to complete step 2?
3. I think after I installed the customer recovery and flash magix, rooting "should" be easier for me, but please point me to the appropriate guide to accomplish that.
Extra Question: I read in one of the forums that after I unlock the bootloader, I will no longer able to receive On The Air updates, how can I continue to receive these updates after bootloader is unlocked and what happens when ZTE roll out Android N for the Axon 7? Will I be able to update to that version?
Here are all the facts about my phone:
Model: ZTE A2017U
Android Version: 6.0.1
Kernel Version: 3.18.20
Build Number: A2017UV1.0.0B27
Thank you all so very much for your patience, understanding, and kind help, I'm forever grateful!

First flash TWRP by following this guide: http://forum.xda-developers.com/axon-7/development/wip-axon-7-root-bootloader-unlokced-t3441204
Then unlock your bootloader by following this guide: http://forum.xda-developers.com/axon-7/how-to/guide-how-to-unlock-bootloader-stay-t3461165
I've never used Magisk before (I just stick with SuperSU), so I'll leave that part to someone else.
As for the extra question:
If you used ZTE's official bootloader unlock method (which required you to submit a form with your IMEI), you'll no longer get OTAs, but if you do it all unofficially (like these guides), you'll still get OTAs. HOWEVER, the OTAs will not install if you make changes to the device besides bootloader unlock. If you have a custom recovery it won't apply. If you have systemless root (which modifies the boot image) it won't apply. If you use Magisk (which modifies the boot image) it won't apply. If you make changes to /system it won't apply. So basically, besides having an unlocked bootloader, you have to be full and complete stock to install OTAs.
However, after an OTA comes out, I suspect that someone will make a TWRP-flashable version.

@xtermmin Thank you so much for your reply, I greatly appreciate it!
Quick question, Is there a way to install TWRP without having to root first? The reason I ask was according to Magix, it must be flashed prior to the system being rooted.

@xtermmin Thank you so much for your reply, I greatly appreciate it!
Quick question, Is there a way to install TWRP without having to root first? The reason I ask was according to Magix, it must be flashed prior to the system being rooted.
Click to expand...
Click to collapse
You don't need to root to flash TWRP.

Axon 7 A2017U B29 Root, BL unlock, and TWRP

Can someone walk me through how to Unlock the bootloader, root, and install TWRP? I'm so confused. I tried to do the newbie way, even though I'm not a newbie, and I lost my B29 Stock Recovery and can't find the download for it.
Sent from my ZTE A2017U using Tapatalk

I haven't done it yet but I've done a lot of reading and this seems to me the best guide.
Head over to this link which is the TWRP thread. https://forum.xda-developers.com/axon-7/development/recovery-official-twrp-zte-axon-7-t3515715
Once you're in there go to bootloader unlock section. Download all the necessary files and on the bottom of the guide there will be instructions link which will take you here https://build.nethunter.com/misc/axon7/INSTRUCTIONS.txt
Follow that and that should do it.
When i get a weekend off ill be using this method to get the Lineage OS 14.1 on my device.

Search, Read & Follow --CAREFULLY--.
It's been a while, but this worked great for me, starting from B29.
Goodluck
Let me tell you, this is the guide that should be pinned. It gives very easy/clear instructions on what you need to do to root/flash recovery and even going back to stock. Very well written and I wish I had seen it sooner. I was going to write a clear guide on this subject only to find.. it already existed.. --nolimit78

@amphi66 I am on 2017U B29 and want to unlock bootloader, install TWRP and root. I also read newbies thread. I am confused about one thing. which TWRP recovery image should I use? a2017u B27 http://d-h.st/kRgq or TWRP recovery 3.0.2-2 : http://d-h.st/dgWW ? There is no file for B29 on newbie's thread and in FAQ, the OP said B27 should work for B29. Which one did you use?
After reading, I also see some people said tenfar's tool is too dangerous and it may brick your phone. Some people also claimed the back up of TWRP recovery 3.0.2 provided on that thread has some bugs may cause you to loose your IMEI number when you do recovering. Do you have any issues? Thanks!
amphi66 said:
Search, Read & Follow --CAREFULLY--.
It's been a while, but this worked great for me, starting from B29.
Goodluck
Let me tell you, this is the guide that should be pinned. It gives very easy/clear instructions on what you need to do to root/flash recovery and even going back to stock. Very well written and I wish I had seen it sooner. I was going to write a clear guide on this subject only to find.. it already existed.. --nolimit78
Click to expand...
Click to collapse

greatzt said:
@amphi66 I am on 2017U B29 and want to unlock bootloader, install TWRP and root. I also read newbies thread. I am confused about one thing. which TWRP recovery image should I use? a2017u B27 http://d-h.st/kRgq or TWRP recovery 3.0.2-2 : http://d-h.st/dgWW ? There is no file for B29 on newbie's thread and in FAQ, the OP said B27 should work for B29. Which one did you use?
After reading, I also see some people said tenfar's tool is too dangerous and it may brick your phone. Some people also claimed the back up of TWRP recovery 3.0.2 provided on that thread has some bugs may cause you to loose your IMEI number when you do recovering. Do you have any issues? Thanks!
Click to expand...
Click to collapse
This was back last Nov, but I followed the guide, using the recommended files (was on B29, but used the B27 OK, then reflashed B29 at the end).
The warning involved backing up and then restoring the EFS partiton with tenfar's tool. DON'T! If you stick with system, data, and boot partitions you should be fine.
Good luck. You may want to check with @nolimit78. He has done this much more recently.

Yes, I agree with you @amphi66 that there is a lot of different places to get information about how to root/flash recovery for A2017U B29. Here's what I've done with two different A7's and both have worked each time.
1. Boot the phone to EDL Mode (Both Vol+Power on boot it'll quick flash the red notification light and then act like it's off.. it's not)
2. Use tenfar's tool to flash the recovery. (I renamed the updated TWRP img and named it "recovery". This used tenfar's tool to flash the updated TWRP on your device.
3. Once in TWRP, run the command (reboot disemmcwp and relaunch TWRP) and flash the package to use modifiable bootloader from B20.
4. Once that flashes now you can send the command in Fastboot "fastboot oem unlock" which will unlock the bootloader that doesn't trip anything notifying ZTE
5. At this point you can flash a B29 rom and have a grand ol' time. However, I would recommend using the LineageOS Rom that's available. Trumps everything else out there IMHO.
6. To do that You'll need to flash the Nougat Bootstacks for that rom to boot prior to flashing the Rom itself. I would recommend flashing the nougat bootstacks, reboot to TWRP, flash LineageOS, reboot.
Like I said, I've done with this with two different devices (Thanks ZTE) and both worked out just fine. I did this method with a device with b27 and b29, both ended up updated and flashed with CM/LineageOS with ZERO issues. This post here should also be pinned as the one true guide (THE KING OF THE NORTH) for unlocking/rooting a stock Axon 7. I spent probably about 4-5 hours working, trying to figure out how to get my device unlocked/rooted. However.. at the very end I wrote out instructions trying to help those who would come after me.. I searched the threads to make sure there wasn't already a thread out there.. and then.. it turns out there was.

Someone have the 5 files to unlock the bootloader 2017u on drive

Second time trying to root phone and I want to make sure I've got this 100%

Alright so I apologize in advance if this thread has been posted a million times and believe me, I've spent the last 4-5 days combing through to make sure I could get every detail of this process done correctly. So I'm not just blindly asking for instructions on how to root my phone. Apologies also if I posted this in the wrong place.
For starters, I'm using Moto G4 Plus XT1641 6.0.1 Build Number MPJ24.139-23.3. My carrier is Koodo in Canada (unsure if that's important but I'll need to being it up again for another point). The files I downloaded were from a youtube tutorial and this includes ADB program, TWRP img 3.0.2.0, supersu zip 2.46 and Motorola Drivers 2.5.4, SOME of which I think may have been outdated versions.
So Saturday night I tried to root my phone with those files. I followed some more guides, I unlocked my bootloader and I think I mostly did everything right except for getting the right supersu version as I've seen up to version 2.82. I think this may have been my first mistake but maybe someone correct me if I'm wrong? My other mistake was not making a backup in TWRP. I'd read about possible wifi problems after rooting so I grabbed the elemental package and possibly even flashed that wrong. I can't even remember the steps of what I did but I'm sure it was all wrong.
Main point, after all that I didn't have ccell service, wifi, etc. The common problems that arise when you do it wrong. I ended up just taking my phone in and getting a new phone. Exact same one, same model. And this brings me to where I am now. I've downloaded some new files and I want to make sure that I've got everything right as to avoid misunderstanding some key parts to the process.
Minimal ADB and Fastboot 1.4.2, twrp-3.1.1-0-athene.img, SuperSU-v2.82-201705271822, Motorola Drivers 2.5.4, and lastly XT1641_ATHENE-TELUS_MPJ24.139-23.3_cid50_subsidy-TELUS_CFC.xml. Notice how that last one says Telus? It's the parent company of Koodo so I'm hoping I can use that as a failsafe.
I think I've covered all the key points so to sum up:
1. Did I use the wrong supersu zip version and could that be a reason why I had no wifi/cell service? Is that also possible because I may have flashed the wrong carrier athene file?
2. Are the files I have downloaded now the correct ones I need and up to date?
3. I'm following this guide. With the files I have downloaded, is it still a correct step by step process? Are there other guides that work better?(thats not a knock on the original guide I'm refering to). https://forum.xda-developers.com/moto-g4-plus/how-to/root-systemless-rooting-supersu-2-74-2-t3405772
I think I've got the right know how and tools to root my phone but I'm just nervous of doing what I did before again and would like some reassurance that I'm doing it right. I've just come from jailbreaks, the world of root is much different. I appreciate any help or tips you guys can throw me!

Hmm, that's odd how you lost radio signal when you rooted, did you obtain radio signal back after you unrooted?
A few things I noted:
1)You may wish to update your device to a newer build, you might get an OTA inviting you to update to MPJ24-139-63 (or 139-64), which was the latest Marshmallow build. Once you've rooted, you will not be able to install OTA updates until you have unrooted and restored the stock recovery (from the same build as you currently have). If you get an OTA notification for any build beginning with NPJ, that's for Nougat.
2)If you plan to stay on Marshmallow, you don't need the ElementalX kernel - a custom kernel like ElementalX is compulsory on Nougat, whereas Marshmallow is not as strict with regards to rooting.
3) I hope the carrier ROM is okay, though from other reports, flashing the incorrect ROM can corrupt device partitions, leaving with no IMEI/no service/no FP. We have possible ways of repairing that though.
The tools you've downloaded seem to be okay and Bender's guide is still okay - even though the tools they've used are out of date - so the general procedure would be (up to you if you've updated MM at this point):
Install adb on your computer.
Boot your device to the bootloader.
Flash TWRP 3.1.1 athene (either the offficial TWRP or an unofficial build from shreps or oadam11) as directed.
Reboot to recovery (to make sure the recovery sticks).
Back up all partitions on your device, make the name descriptive.
Make another backup of the boot partition - this contains your stock kernel, useful for switching root manager.
Once the backups have been made, flash SuperSU v2.82.
Wipe cache/Dalvik
Reboot.

echo92 said:
Hmm, that's odd how you lost radio signal when you rooted, did you obtain radio signal back after you unrooted?
A few things I noted:
1)You may wish to update your device to a newer build, you might get an OTA inviting you to update to MPJ24-139-63 (or 139-64), which was the latest Marshmallow build. Once you've rooted, you will not be able to install OTA updates until you have unrooted and restored the stock recovery (from the same build as you currently have). If you get an OTA notification for any build beginning with NPJ, that's for Nougat.
2)If you plan to stay on Marshmallow, you don't need the ElementalX kernel - a custom kernel like ElementalX is compulsory on Nougat, whereas Marshmallow is not as strict with regards to rooting.
3) I hope the carrier ROM is okay, though from other reports, flashing the incorrect ROM can corrupt device partitions, leaving with no IMEI/no service/no FP. We have possible ways of repairing that though.
The tools you've downloaded seem to be okay and Bender's guide is still okay - even though the tools they've used are out of date - so the general procedure would be (up to you if you've updated MM at this point):
Install adb on your computer.
Boot your device to the bootloader.
Flash TWRP 3.1.1 athene (either the offficial TWRP or an unofficial build from shreps or oadam11) as directed.
Reboot to recovery (to make sure the recovery sticks).
Back up all partitions on your device, make the name descriptive.
Make another backup of the boot partition - this contains your stock kernel, useful for switching root manager.
Once the backups have been made, flash SuperSU v2.82.
Wipe cache/Dalvik
Reboot.
Click to expand...
Click to collapse
Thanks for the reply, it helps me feel a little more confident in what I'm doing. I didn't get my cell service back as I just took my phone into Koodo and they just gave me a new one. A few questions.
Are there some clear guides on how to recover from lost wifi and cell service? I've seen a few but it appears they all have different directions so as a newcomer to Android it does seems a bit confusing to what the right way to do it is. I'm also hoping someone can chime in on the Telus carrier IMG file as that seems to be my backup in case anything goes terribly wrong again. I'd hate to have to bring my phone back again a second time. Also, is it an easy process to make a backup of the kernel in TWRP? I've figured out how to make a backup of the normal partition, just hoping backing up the kernel is just as easy.
I think I'm near ready to take the root plunge in the coming days. It's good to see such a strong community here. Totally different from the jailbreak scene.

lemonlimejones said:
Thanks for the reply, it helps me feel a little more confident in what I'm doing. I didn't get my cell service back as I just took my phone into Koodo and they just gave me a new one. A few questions.
Are there some clear guides on how to recover from lost wifi and cell service? I've seen a few but it appears they all have different directions so as a newcomer to Android it does seems a bit confusing to what the right way to do it is. I'm also hoping someone can chime in on the Telus carrier IMG file as that seems to be my backup in case anything goes terribly wrong again. I'd hate to have to bring my phone back again a second time. Also, is it an easy process to make a backup of the kernel in TWRP? I've figured out how to make a backup of the normal partition, just hoping backing up the kernel is just as easy.
I think I'm near ready to take the root plunge in the coming days. It's good to see such a strong community here. Totally different from the jailbreak scene.
Click to expand...
Click to collapse
Hmm, I'm not aware of any guides specifically dealing with lost Wi-Fi and lost mobile signal. There are a few posts where we've had some success in getting radios back, but it involves either hex editing https://forum.xda-developers.com/showpost.php?p=72340548&postcount=98 or flashing hw, modem or fsg partitions from a working device (in this case, XT1641) The instances I've seen of lost Wi-Fi/mobile signal appear to have occurred during a stock ROM fastboot flash, but hoping someone can chime in as to whether it was just flashing the wrong region firmware or something else.
If you want to back up your kernel in TWRP:
Boot to TWRP
Tap 'Backup' on the main menu
Select only the 'boot' partition - this is the partition that contains your kernel (should be stock and clean if you've not rooted).
Rename the file to remind you it's your kernel.
Swipe to back up.
If you need to revert to this kernel, unroot first (depending on your root manager, you may have to boot and then unroot. I recall SuperSU unroots via the SuperSU app settings), then boot to TWRP.
Tap 'Restore' on the main menu
Navigate to your boot backup
Flash your boot backup
You should now have a clean stock kernel, so if you wish to switch root managers, you should be able to obtain root with your new root manager. We want a clean kernel (no modifications made) since uninstalling the old root may leave traces of root on your existing kernel, and thus may cause issues if you re-root with a different manager.
Good luck in rooting

echo92 said:
Hmm, I'm not aware of any guides specifically dealing with lost Wi-Fi and lost mobile signal. There are a few posts where we've had some success in getting radios back, but it involves either hex editing https://forum.xda-developers.com/showpost.php?p=72340548&postcount=98 or flashing hw, modem or fsg partitions from a working device (in this case, XT1641) The instances I've seen of lost Wi-Fi/mobile signal appear to have occurred during a stock ROM fastboot flash, but hoping someone can chime in as to whether it was just flashing the wrong region firmware or something else.
If you want to back up your kernel in TWRP:
Boot to TWRP
Tap 'Backup' on the main menu
Select only the 'boot' partition - this is the partition that contains your kernel (should be stock and clean if you've not rooted).
Rename the file to remind you it's your kernel.
Swipe to back up.
If you need to revert to this kernel, unroot first (depending on your root manager, you may have to boot and then unroot. I recall SuperSU unroots via the SuperSU app settings), then boot to TWRP.
Tap 'Restore' on the main menu
Navigate to your boot backup
Flash your boot backup
You should now have a clean stock kernel, so if you wish to switch root managers, you should be able to obtain root with your new root manager. We want a clean kernel (no modifications made) since uninstalling the old root may leave traces of root on your existing kernel, and thus may cause issues if you re-root with a different manager.
Good luck in rooting
Click to expand...
Click to collapse
That's perfect thank you so much. Am I right to assume that if I get into a jam then I can just restore/reflash my backups and I'll be back to normal?

To be safe, flash the ElementalX kernel before rooting.

reCoded said:
To be safe, flash the ElementalX kernel before rooting.
Click to expand...
Click to collapse
See this is where I get confused, the guy above you said ElementalX isn't needed on Marshmallow but you say i should use it anyway? I've seen a few differing opinions on what should and shouldn't be done, just not sure which one is the right answer.

lemonlimejones said:
See this is where I get confused, the guy above you said ElementalX isn't needed on Marshmallow but you say i should use it anyway? I've seen a few differing opinions on what should and shouldn't be done, just not sure which one is the right answer.
Click to expand...
Click to collapse
ElementalX v0.07 is not required on Marshmallow (provided you are planning on staying on 6.0.1), you can root the stock ROM kernel. You may wish to flash the ElementalX kernel anyway as this custom kernel gives you more control and tuning options compared to the stock kernel. On stock Nougat, because the anti-rooting kernel security is much stricter and enforced (whereas on Marshmallow I don't think it's enforced), then you need ElementalX or vegito or a custom kernel to bypass the security, by in effect replacing the stock secure kernel with a kernel that doesn't have those restrictions. Without replacing the stock kernel on stock Nougat systems, you can run into a bootloop.
As an MM kernel as mentioned before has weaker security regarding rooting, it's up to you if you choose to root the stock kernel or ElementalX.
I've rooted MM (MPJ24.139-63) in the past with SuperSU (v2.79) and only used TWRP and SuperSU.
In response to your other post, the backups should get you out of a jam, since what you're doing should only affect the partitions you've backed up previously (they in theory shouldn't go anywhere near your modem, bootloader or critical firmware). Bear in mind that the TWRP backup if restored in full will revert your messages and data to that backup. You may wish to use Titanium Backup or other tools to take occasional snapshots of your apps data that you can restore should you have to roll back.

lemonlimejones said:
See this is where I get confused, the guy above you said ElementalX isn't needed on Marshmallow but you say i should use it anyway? I've seen a few differing opinions on what should and shouldn't be done, just not sure which one is the right answer.
Click to expand...
Click to collapse
If you're on Nougat, then you should use ElementalX. If you're on Marshmallow, you don't need it.

echo92 said:
ElementalX v0.07 is not required on Marshmallow (provided you are planning on staying on 6.0.1), you can root the stock ROM kernel. You may wish to flash the ElementalX kernel anyway as this custom kernel gives you more control and tuning options compared to the stock kernel. On stock Nougat, because the anti-rooting kernel security is much stricter and enforced (whereas on Marshmallow I don't think it's enforced), then you need ElementalX or vegito or a custom kernel to bypass the security, by in effect replacing the stock secure kernel with a kernel that doesn't have those restrictions. Without replacing the stock kernel on stock Nougat systems, you can run into a bootloop.
As an MM kernel as mentioned before has weaker security regarding rooting, it's up to you if you choose to root the stock kernel or ElementalX.
I've rooted MM (MPJ24.139-63) in the past with SuperSU (v2.79) and only used TWRP and SuperSU.
In response to your other post, the backups should get you out of a jam, since what you're doing should only affect the partitions you've backed up previously (they in theory shouldn't go anywhere near your modem, bootloader or critical firmware). Bear in mind that the TWRP backup if restored in full will revert your messages and data to that backup. You may wish to use Titanium Backup or other tools to take occasional snapshots of your apps data that you can restore should you have to roll back.
Click to expand...
Click to collapse
Right on, I think I feel comfortable with this now! One more question though, with newer versions of SuperSU is it still necessary to make the command echo systemless=true or was that mostly for older versions? Also if that part is needed, should I run SuperSU from the data folder in TWRP?

lemonlimejones said:
Right on, I think I feel comfortable with this now! One more question though, with newer versions of SuperSU is it still necessary to make the command echo systemless=true or was that mostly for older versions? Also if that part is needed, should I run SuperSU from the data folder in TWRP?
Click to expand...
Click to collapse
The 'echo systemless=true', as I understand it, isn't required on SuperSU 2.79 or newer, so if you're flashing 2.82, you should be able to flash as is without having to run the command too Also makes uninstalling easier!

Need help rooting my phone. Model: SM-C9000 c9ltechn, 8.0 oreo Samsung experience 9.0

First of all, I want to tell you that I'm not very familiar with rooting but have just a bit experience flashing custom roms, so please go easy on me.
I have done some research and found a couple things that I couldn't find answers for:
1) First one is that apparently you need your bootloader unlocked/ OEM unlocking enabled in developer options, however since I upgraded to Oreo in last August, that option disappeared. I've tried two methods for making it appear that I've found online (keeping phone up for 7 days straight and reverting time back) but none worked. I've read somewhere that if you downgrade to Nougat, enable it then re update to Oreo your bootloader will remain unlocked. So, can someone confirm this? Can you downgrade with a locked bootloader? And if so, can someone guide me through it? (Additional question: will the downgrade reset user data?)
2) After unlocking bootloader you need to flash TWRP but I have so many questions on that. First: I couldn't find a TWRP for oreo. Does it work regardless of os version? Second: I found a guide from XDA that is written long ago, and it says "make a full backup of your system, including EFS before flashing". How do you backup without flashing it tho? All guides are about using either a custom recovery or rooted app.
3) Do you really need TWRP? I mean, can't you flash Magisk via Odin/ADB directly, perhaps without unlocking bootloader? What happens if I use install command from ADB?
4) So does tripping knox fuse achieve anything other than killing the nonexistent system updates and samsung guarantee? I want to make sure Samsung health is going to operate.

Can I downgrade to 7.0 stock firmware from lineage?

What happens if I have lineage 15.1 and I want to return to 7.0 stock can I do it?
should I do a back up? I read that I could lose the imei :crying: how can I avoid it?
I would use this tutorial
https://www.youtube.com/watch?v=F_6LQr01GhY
thank you all for the help and advice :good::fingers-crossed:
sorry for my bad English

I don't know about lineage 15.1, but I had the OTA 8.1 update on my XT1644, and it broke my speakerphone and made my phone run like crap, so I just rolled back to stock 7.0 and am VERY happy.
I DID lose IMEI (I had IMEI=0), but from what I understand, it was because I manually flashed 7.0 from adb. I think that had I used the TWRP file, it wouldn't have happened.
I got IMEI back by following the directions in this thread:
https://forum.xda-developers.com/moto-g4-plus/how-to/guide-moto-g4-plus-imei0-issue-t3859068
I also disabled OTA backups by doing this: https://forum.xda-developers.com/showpost.php?p=72373828&postcount=12
So that Motorola can't push an OTA on my phone and brick it.
You should make a complete backup following the directions of this thread:
https://forum.xda-developers.com/moto-g4-plus/how-to/guide-moto-g4-plus-complete-partition-t3875787
I know virtually nothing about messing with phones or Android. My motivation was that if I couldn't get rid of OTA 8.1, I was going to throw away my phone and get something different. And I didn't want to spend the money on a new phone. I figured I'd brick what I have, before I spent money on a new one.
I pretty much followed the directions on this thread:
https://forum.xda-developers.com/moto-g4-plus/how-to/guide-newbie-resource-thread-t3386584
Except that by loading 7.0 manually, it caused me to lose IMEI. Knowing what I know now, after flashing TWRP, I would have flashed 7.0 using TWRP. And I don't think I would have lost IMEI then.
Once I had 7.0 loaded, I flashed Magisk to get root.
Once I had root, I used a file explorer to go in and delete the app that pushes the OTA, so Motorola can't screw me. As far as I know, I am now permanently on 7.0.
Do this at your own risk. But you're already running Lineage, so I assume that you know way more about this than I do.
Edit: Just realized I kinda rambled here. So here's the condensed version of what I would do, I think... do at your own risk.
1. Use that thread I linked to back up your *everything*
2. Save stock 7.0 file, Elemental X file, and Magisk file on your SD card (all from XDA)
3. From TWRP, flash 7.0
4. Once you have 7.0, from TWRP flash Elemental X.
5. From TWRP, flash Magisk
6. From that link I posted, delete the file that stops OTA's.
I think you'll now be where I am, with rooted stock 7.0. But you should still have your IMEI. If you have IMEI=0, follow the directions in the link I posted.

slimbobaggins said:
I don't know about lineage 15.1, but I had the OTA 8.1 update on my XT1644, and it broke my speakerphone and made my phone run like crap, so I just rolled back to stock 7.0 and am VERY happy.
Click to expand...
Click to collapse
I am eternally grateful for your help and message!! :good::good::good:
but in the tutorial that you sent me: https://forum.xda-developers.com/moto-g4-plus/how-to/guide-newbie-resource-thread-t3386584
indicate that the installation should be done manually by adb... do you think I should do it for TWRP ??
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[...]
Flashing Stock Firmware:
1) Download the correct firmware for your device from http://www.filefactory.com/folder/c6cdedc45a775d27
2) Download adb and fastboot from https://drive.google.com/file/d/0B5j...ew?usp=sharing
3) Extract the firmware into the folder containing abd and fastboot.
4) Reboot the phone into Bootloader (power off, then press the power and volume down buttons simultaneously).
5) Execute these commands and make sure you receive an 'OKAY' after each command.
[...]
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thanks

That tutorial was written years ago. I think back then, the only way was to manually install.
If you manually install 7.0, you will wipe your IMEI and have to restore it like I did.
I suggested the TWRP install because I *think* it wont wipe the IMEI.
If it does, you should still be able to recover it... but again, I barely know what I'm talking about. So please follow the thread about backing up your entire phone and persist, first. I am merely sharing with you what I did to roll back mine to 7.0, your experience may vary.
And again, if you do roll back, make sure you follow the instructions to disable OTA, because if you accidentally take an OTA, it will brick your phone for sure.
I literally just figured out how to do all this, this weekend. Prior to that I knew *nothing* about this stuff. So please read everything you can to educate yourself... its all here on this very good forum, you just have to piece it together. I am 100% a newbie.