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Update 4.2 failet with trinity kernel

Please help, my nexus was unlocked rooted with trinity kernel. When i pushed update, my tablet restarted with clockwokmod and failed to update
to 4.2. i believed it was because of custom kernel so i then flashed to stock factory, and re locked using nexus toolkit.
When i go to setting for update, it's showing me that my system is up to date 4.1.2. I don't understand. I thought flashing it back to stock factory will solve the problem.
Thanks a lot in advance for you hep

diamondx911 said:
Please help, my nexus was unlocked rooted with trinity kernel. When i pushed update, my tablet restarted with clockwokmod and failed to update
to 4.2. i believed it was because of custom kernel so i then flashed to stock factory, and re locked using nexus toolkit.
When i go to setting for update, it's showing me that my system is up to date 4.1.2. I don't understand. I thought flashing it back to stock factory will solve the problem.
Thanks a lot in advance for you hep
Click to expand...
Click to collapse
1) If you are using a custom kernel and/or custom recovery and/or removed/froze required system apks and/or modified build.prop and/or have a dozen other "custom" things, then the OTA update will NOT work. Period. You need to revert ALL of that. Stock kernel, recovery, system apks, build.prop, etc. Because if any of those aren't stock, the install will abort.
2) Having root is irrelevant. The update will remove suid access on the binary, so you will need to "re-root", but the binaries presence is irrelevant.
3) If it failed the OTA update, it won't download it again right away. Your best bet is to download the file and try to flash manually in a custom recovery (which will work as long as everything else is stock).
4) Did you say you relocked the tablet? If so, why? That was NOT required, and you just f*cked yourself, because you won't be able to flash a custom recovery back without unlocking the bootloader again, which will wipe your sdcard. There is NO reason to relock unless you are returning the device.
5) Again, this is why I hate toolkits. Learn to do things manually and you will be much better off.
At this point, assuming you relocked the bootloader, you will probably need to do a full factory reset and unlock it again. Then flash custom recovery and then flash the update. Or, since it would have been reset at that point, just download the full image from Google and flash that, then flash custom recovery.

phonic said:
1) If you are using a custom kernel and/or custom recovery and/or removed/froze required system apks and/or modified build.prop and/or have a dozen other "custom" things, then the OTA update will NOT work. Period. You need to revert ALL of that. Stock kernel, recovery, system apks, build.prop, etc. Because if any of those aren't stock, the install will abort.
2) Having root is irrelevant. The update will remove suid access on the binary, so you will need to "re-root", but the binaries presence is irrelevant.
3) If it failed the OTA update, it won't download it again right away. Your best bet is to download the file and try to flash manually in a custom recovery (which will work as long as everything else is stock).
4) Did you say you relocked the tablet? If so, why? That was NOT required, and you just f*cked yourself, because you won't be able to flash a custom recovery back without unlocking the bootloader again, which will wipe your sdcard. There is NO reason to relock unless you are returning the device.
5) Again, this is why I hate toolkits. Learn to do things manually and you will be much better off.
At this point, assuming you relocked the bootloader, you will probably need to do a full factory reset and unlock it again. Then flash custom recovery and then flash the update. Or, since it would have been reset at that point, just download the full image from Google and flash that, then flash custom recovery.
Click to expand...
Click to collapse
Haha, thanks for answering... the update came back by itself.
I was not aware of anything when i unlocked and rooted my nexus. please bare with me. I'm new to the android scene. but i'm very familiar with the hacking tool, i hacked and unlocked everything i own in my house, from 3 iphones, to my psp , xbox, ps3 and psp. when i first got my hand on the nexus i saw some dead black line of pixel that was appearing for half a second, after i read that a custom kernel can fix it,
I just did it fast and was not in a mood to start learning that sh*t from scratch. so now i'm on 4.2 , i know i lost everything. i will just have to unlock again and and root it....

diamondx911 said:
Haha, thanks for answering... the update came back by itself.
I was not aware of anything when i unlocked and rooted my nexus. please bare with me. I'm new to the android scene. but i'm very familiar with the hacking tool, i hacked and unlocked everything i own in my house, from 3 iphones, to my psp , xbox, ps3 and psp. when i first got my hand on the nexus i saw some dead black line of pixel that was appearing for half a second, after i read that a custom kernel can fix it,
I just did it fast and was not in a mood to start learning that sh*t from scratch. so now i'm on 4.2 , i know i lost everything. i will just have to unlock again and and root it....
Click to expand...
Click to collapse
Understood, and "hacking" android, especially Google devices, is pretty easy once you know what you are doing. The reason I dislike toolkits is that it prevents people from understanding the process, which really is fairly easy to understand, and can complicate troubleshooting steps.
The bootloader can easily be unlocked and locked. It takes one command and it's done. In order to flash anything with fastboot, you need it to be unlocked. The problem is, when you do this, it factory resets the device. So if you inadvertantly relock it, your going to need to reset it to unlock it again.
Even without the toolkit, going from unopened stock Nexus7 to fully rooted, updated and custom firmware Nexus7 only takes maybe 10 minutes, and 9 minutes of that is waiting for it to finish doing the various steps (flashing, rebooting, etc.). The most time consuming part is, unless you have good backups, restoring all your apps and settings. Titanium Backup is the best tool (IMHO) for that.
But yeah, in this case, you're going to need to unlock/wipe again. However, you CAN backup your "sdcard" to your computer and push the files back to it after the wipe. That can be very time consuming depending on how much you have.

[Q] 5.1 OTA Update Boots into Recovery

I have never done an OTA update as when I first got into Android I was flashing ROMs nearly every week and never waited for updates just flashed a new ROM, however when I got my Nexus 6 I decided to just root and stick with stock.
I woke this morning and the 5.1 update was available but when I download it and select install and reboot it boots into recovery (TWRP) and I can't see where the download is - I presume I am having to flash it myself? So I have to reboot and it says I am up-to-date with 5.0.1 and then an hour later the download is available again and I go through the same process.
Can anyone help, tell me where i am going wrong.

I had same issue after relocking bootloader and this worked for me and hopefully it may work for you. Put phone in fastboot mode.(hold power + volume down) then use fastboot command fastboot -w

How do you define stock if you have TWRP. LOL
Sent from my Nexus 6

DebianDog said:
How do you define stock if you have TWRP. LOL
Sent from my Nexus 6
Click to expand...
Click to collapse
Well OK stock except for the recovery. I presumed you would know what I meant. I will ensure my posts are word prefect next time.

md1008 said:
I had same issue after relocking bootloader and this worked for me and hopefully it may work for you. Put phone in fastboot mode.(hold power + volume down) then use fastboot command fastboot -w
Click to expand...
Click to collapse
Thanks I'll give it a go

Same issue here. Let us know how you make out.

Hate to do a "me too" post, but I've had the exact same experience.
I'll wait to see whether the fastboot -w method works before I do anything else.
I did try to find the (410.4Mb) download on my N6, but I suspect that the failed update must have deleted it, as it's asking me to download it again.

fastboot -w just wiped userdata so needed to do a fresh install and was still at 5.0.1. So just had to install my backup again to get back to where I was this morning.

Ouch! Sorry to hear it (though glad that you had a backup) - thanks for saving the rest of us from trying that particular route.
I'm still looking for a way to get to 5.1.

You can't do an OTA update with a NON-STOCK recovery.
You can however, if your bootloader is unlocked, download the factory image, extract it, and flash the system.img, bootloader.img, radio.img, cache.img etc...use fastboot to flash those.
Or you can fastboot flash the stock recovery, and take the OTA again.

Thanks.
I assume that I can also use Nexus Root Toolkit to "Flash Stock + Unroot" (without wiping the device), then take the OTA update to 5.1, and then use NRT to Root again?
Just doing a full backup at the moment before I start playing!

UPDATE: The above worked fine.
I started with 5.0.1, rooted, unlocked Bootloader
Then, in Nexus Root Toolkit, I used:
1) Backup (using Create Nandroid Backup w/Custom Recovery option)
2) Flash Stock + Unroot (using No Wipe Mode. I also had to enable Force Flash Mode)
Then, on the phone, accept the OTA 5.1 update, which downloaded and installed first time.
Back to NRT, and:
3) Root and also flash Custom Recovery
I ended up with 5.1, rooted, unlocked Bootloader (and all my apps and data were untouched).

Since doing the method recommended in the second post the OTA update hasn't been available on my device?

Have you tried rebooting the phone?
Or going into Settings > About Phone > System Updates > Check for Updates
It's always possible (if unlikely) that Google have stopped the roll-out to fix some of the issues that people have been reporting with SmartLock, etc?

Philip said:
Have you tried rebooting the phone?
Or going into Settings > About Phone > System Updates > Check for Updates
It's always possible (if unlikely) that Google have stopped the roll-out to fix some of the issues that people have been reporting with SmartLock, etc?
Click to expand...
Click to collapse
yes and yes done that too

Philip said:
UPDATE: The above worked fine.
I started with 5.0.1, rooted, unlocked Bootloader
Then, in Nexus Root Toolkit, I used:
1) Backup (using Create Nandroid Backup w/Custom Recovery option)
2) Flash Stock + Unroot (using No Wipe Mode. I also had to enable Force Flash Mode)
Then, on the phone, accept the OTA 5.1 update, which downloaded and installed first time.
Back to NRT, and:
3) Root and also flash Custom Recovery
I ended up with 5.1, rooted, unlocked Bootloader (and all my apps and data were untouched).
Click to expand...
Click to collapse
Why did you take the scenic route? This is by far the longest method to do that.
Instead of flashing stock with nrt, why not just flash stock normally? That way you could have just flashed 5.1 without having to take any OTA...
And further, if you wanted to keep recovery, why not just flash the system and boot image keeping everything else as it is? Then just flash SuperSU from twrp?
2 commands
fastboot flash system system.img
fastboot flash boot boot.img
Boot into recovery and flash root.
Much quicker than the method you used.

rootSU said:
Why did you take the scenic route? This is by far the longest method to do that.
Click to expand...
Click to collapse
Well, my fist step was a backup, which you conveniently left out - you may be happy to update your phone without backing it up first, but I chose not to take that chance.
Apart from that, it's about the same number of steps - I was happy to take 5.1 OTA (which meant that I was certain that it was the correct version for my phone), and Nexus Root Toolkit is a much nicer piece of software to use than fastboot. I know that some people don't like NRT because they feel that it demystifies the black arts of updating and it threatens their voodoo status, but I find it an excellent piece of software and recommend it to you.
In the meantime, while you had to go and find the appropriate system.img and the appropriate boot.img and download them before fastbooting them, these were steps that I was able to avoid whilst enjoying my "scenic" journey.
So you take the high road and I'll take the low road - but I reckon that it took me no longer to update my phone than it took you to update yours!

Philip said:
Well, my fist step was a backup, which you conveniently left out - you may be happy to update your phone without backing it up first, but I chose not to take that chance.
Apart from that, it's about the same number of steps - I was happy to take 5.1 OTA (which meant that I was certain that it was the correct version for my phone), and Nexus Root Toolkit is a much nicer piece of software to use than fastboot. I know that some people don't like NRT because they feel that it demystifies the black arts of updating and it threatens their voodoo status, but I find it an excellent piece of software and recommend it to you.
In the meantime, while you had to go and find the appropriate system.img and the appropriate boot.img and download them before fastbooting them, these were steps that I was able to avoid whilst enjoying my "scenic" journey.
So you take the high road and I'll take the low road - but I reckon that it took me no longer to update my phone than it took you to update yours!
Click to expand...
Click to collapse
It took you loads longer haha.

rootSU said:
It took you loads longer haha.
Click to expand...
Click to collapse
And that bothered you so much that you had to tell the whole world about it? Wow!

Philip said:
And that bothered you so much that you had to tell the whole world about it? Wow!
Click to expand...
Click to collapse
To be honest no. The route you took was so long that I thought you just didn't have a clue about what you were doing so I thought I'd help out and let you know the quicker version... And if anyone reads your post and thinks its the best way to do it, well now they have some contrast.
What bothers me is your attitude however. But I don't care enough to get into an argument with people who would rather waste their time and the people they try to help than listen to constructive criticism.
But yeah, your way is needlessly long so I hope people don't take your lead.

Is there a root method that doesn't require unlocking the bootloader? (LRX22C)

I just got my N6 a few days ago, and JUST got everything all set up how I like. I went to go root it, and the method mentioned in the "All-In-One" stickied thread requires you to unlock the bootloader, which says it will factory reset the device.
I don't want to factory reset at this point, I just want to root it. I've never had to wipe a phone or unlock a bootloader to root a phone before, so this is new to me.
Thanks

arcooke said:
I just got my N6 a few days ago, and JUST got everything all set up how I like. I went to go root it, and the method mentioned in the "All-In-One" stickied thread requires you to unlock the bootloader, which says it will factory reset the device.
I don't want to factory reset at this point, I just want to root it. I've never had to wipe a phone or unlock a bootloader to root a phone before, so this is new to me.
Thanks
Click to expand...
Click to collapse
There is a way, I believe, by running TWRP on your PC and flashing SuperSU from your PC. However, it's not a recommended method as you will have no way of backing up. Also, if you get caught in a bootloop, you won't be able to recover without a custom recovery.

arcooke said:
I just got my N6 a few days ago, and JUST got everything all set up how I like. I went to go root it, and the method mentioned in the "All-In-One" stickied thread requires you to unlock the bootloader, which says it will factory reset the device.
I don't want to factory reset at this point, I just want to root it. I've never had to wipe a phone or unlock a bootloader to root a phone before, so this is new to me.
Thanks
Click to expand...
Click to collapse
and you don't have to "hack" a nexus as well, as google provided an easy way to unlock your bootloader and to obtain root. if you just got your nexus a few days ago, just unlock the bootloader and root it. loosing a few days of information is more than worth it for root. don't waste your time worrying over a few days of data.

Can be done but not recommended.

adb backup/restore can save a little bit of information for you, but I wouldn't go in expecting it to save everything
Sent from my Nexus 6

What did you set up? You can back up your messages, and your apps will re-download. Your photos are already syncing to Google. If it's not rooted, I can't imagine you've done that much customization.

Lesson learned: unlock should ALWAYS be the very first step you do on a new phone.

arcooke said:
I just got my N6 a few days ago, and JUST got everything all set up how I like. I went to go root it, and the method mentioned in the "All-In-One" stickied thread requires you to unlock the bootloader, which says it will factory reset the device.
I don't want to factory reset at this point, I just want to root it. I've never had to wipe a phone or unlock a bootloader to root a phone before, so this is new to me.
Thanks
Click to expand...
Click to collapse
if you download kingroot from the internet and install it onto your phone through unknown sources. it says your not supported but just click start root anyway. and hey presto your rooted. ive done this on my nexus 6 and its worked and hasnt knackered the phone and i know a couple of other people whove done the same
the only thing i havnet worked out how to do is take the king userr off. once your finished rooting, in order to sustain root that app becomes a permanent addittion to the phone. ive deleted it before and lost root. but just reinstall and follow the steps again and you gain root again
to check root download root checker form the app market

danr93 said:
if you download kingroot from the internet and install it onto your phone through unknown sources. it says your not supported but just click start root anyway. and hey presto your rooted. ive done this on my nexus 6 and its worked and hasnt knackered the phone and i know a couple of other people whove done the same
the only thing i havnet worked out how to do is take the king userr off. once your finished rooting, in order to sustain root that app becomes a permanent addittion to the phone. ive deleted it before and lost root. but just reinstall and follow the steps again and you gain root again
to check root download root checker form the app market
Click to expand...
Click to collapse
Yes we're aware but we do recommend against these one-click methods usually. Rooted users cannot accept OTA updates, so the only way to update is with an unlocked bootloader unless you're going to have a custom recovery (also highly recommended) so you can flash flashable zips.
Also you MUST go into settings and enable the "Allow OEM unlock" in developer options, because If you break your OS with root, which is easily done - you're going to become stuck as you can't unlock the bootloader. Not too bad if you have TWRP recovery installed, but then that becomes a single point of failure.

danarama said:
Yes we're aware but we do recommend against these one-click methods usually. Rooted users cannot accept OTA updates, so the only way to update is with an unlocked bootloader unless you're going to have a custom recovery (also highly recommended) so you can flash flashable zips.
Also you MUST go into settings and enable the "Allow OEM unlock" in developer options, because If you break your OS with root, which is easily done - you're going to become stuck as you can't unlock the bootloader. Not too bad if you have TWRP recovery installed, but then that becomes a single point of failure.
Click to expand...
Click to collapse
ok thats fair enough i didnt realise it was so risky. i downloaded twrp straight after this method worked for me and got everything backed up

danr93 said:
ok thats fair enough i didnt realise it was so risky. i downloaded twrp straight after this method worked for me and got everything backed up
Click to expand...
Click to collapse
Good stuff. Once rooted, Flashify is a great tool to flash TWRP. With the nexus 5, you could unlock the bootloader with an app that didnt wipe everything, which was great, but Nexus 6 doesn't allow that, but always do go to settings > developer options > OEM Unlock (Set to enable). Without this set, you cannot unlock the bootloader from fastboot. Also, side note, developer options doesn't show up until you go into Settings > About phone then tap "Build number" several times to make the option visible. Think its 7 times.
It's interesting saying that you need kingroot to remain on the device. Thats a bit of a pain. Does it install SuperSU or not? If not, might be interesting to see what happens if you install the SuperSU app from Play - whether it allows it to be removed then.
My preferred method however is definitely unlock the BL, fastboot flash TWRP, From TWRP flash SuperSU zip (or rooted ROM).

For the record, I did end up factory resetting to do it the right way.
Is this easy to unroot if a new OTA update comes out?

arcooke said:
For the record, I did end up factory resetting to do it the right way.
Is this easy to unroot if a new OTA update comes out?
Click to expand...
Click to collapse
Yes and no. To "unroot" you have to fastboot flash system.img and boot.img, which if the factory image is available for the version your OTA will raise you to, you're done. If there is no factory image for that new version, you must flash the system and boot(and recovery) of the expected version, then OTA. Note, recovery version isn't checked. Only system and boot. Just that recovery must be stock for OTA to flash.
To be honest, easiest way is to wait for a rooted flashable zip to be made available and flash via recovery

danarama said:
Yes and no. To "unroot" you have to fastboot flash system.img and boot.img, which if the factory image is available for the version your OTA will raise you to, you're done. If there is no factory image for that new version, you must flash the system and boot(and recovery) of the expected version, then OTA. Note, recovery version isn't checked. Only system and boot. Just that recovery must be stock for OTA to flash.
To be honest, easiest way is to wait for a rooted flashable zip to be made available and flash via recovery
Click to expand...
Click to collapse
Geez. I thought the "pure google experience" would be much less of a headache. lol. Rooting/updating/etc was so much easier on my old Verizon phones.. one-click-root, one-click-unroot, easy updates, never had to factory reset or flash roms to do anything.
I only rooted for AdAway, starting to wonder if that was a good idea or not.

arcooke said:
Geez. I thought the "pure google experience" would be much less of a headache. lol. Rooting/updating/etc was so much easier on my old Verizon phones.. one-click-root, one-click-unroot, easy updates, never had to factory reset or flash roms to do anything.
I only rooted for AdAway, starting to wonder if that was a good idea or not.
Click to expand...
Click to collapse
That's lollipop for you. It changed everything.
It's still really simple.

Good to know. Thanks for the info!

question about maintaining root

So far I've been running my OP3T with stock rom with TWRP recovery and SuperSU to have root. This was mostly because I wanted the Adaway and titanium backup to work. I undid everything so I could update to the latest OxygenOS version, and now I'm on the stock recovery too, but with bootloader still unlocked I believe. I no longer have root after doing the upgrade as far as I can tell, still a bit new to all this flashing, haha. The last time I did this was when the nexus 4 came out
What is the best option for maintaining root while still being able to upgrade smoothly? I'm not against using one of the custom ROMs if that will help, but I do kinda like the stock rom so far!
thanks!

bluesrph said:
So far I've been running my OP3T with stock rom with TWRP recovery and SuperSU to have root. This was mostly because I wanted the Adaway and titanium backup to work. I undid everything so I could update to the latest OxygenOS version, and now I'm on the stock recovery too, but with bootloader still unlocked I believe. I no longer have root after doing the upgrade as far as I can tell, still a bit new to all this flashing, haha. The last time I did this was when the nexus 4 came out
What is the best option for maintaining root while still being able to upgrade smoothly? I'm not against using one of the custom ROMs if that will help, but I do kinda like the stock rom so far!
thanks!
Click to expand...
Click to collapse
This thread should answer all your questions and doubts
https://forums.oneplus.net/threads/...-or-custom-recovery-without-data-loss.479265/

saurabh40629 said:
This thread should answer all your questions and doubts
https://forums.oneplus.net/threads/...-or-custom-recovery-without-data-loss.479265/
Click to expand...
Click to collapse
Thank you, I have seen that post. I'm guessing any route I go I'll have to flash updates then? I was hoping to find a way to be able to use OTA updates.
I've also never been able to get rid of the dm-verity error, even after going back to stock and locking the bootloader. Is there anything I need to worry about with that or is it just an annoyance?
Sent from my OnePlus3T using XDA Labs

bluesrph said:
Thank you, I have seen that post. I'm guessing any route I go I'll have to flash updates then? I was hoping to find a way to be able to use OTA updates.
I've also never been able to get rid of the dm-verity error, even after going back to stock and locking the bootloader. Is there anything I need to worry about with that or is it just an annoyance?
Click to expand...
Click to collapse
Dm-verity u can bypass but bootloader one, you can not. Look at the apps, mods section.

bluesrph said:
Thank you, I have seen that post. I'm guessing any route I go I'll have to flash updates then? I was hoping to find a way to be able to use OTA updates.
I've also never been able to get rid of the dm-verity error, even after going back to stock and locking the bootloader. Is there anything I need to worry about with that or is it just an annoyance?
Sent from my OnePlus3T using XDA Labs
Click to expand...
Click to collapse
You shouldn't try to flash the partial OTAs while you are rooted and have a custom recovery installed. The partial zip will try to make specific changes in the restricted partitions (/system, /boot, /recovery, etc.) related to the update and prior modifications to these files may cause the update to fail and the phone to brick. You can still use the "Update" tab in the Settings menu to download the update though as OOS will detect root and download the full zip of the update for you. Simply flash the full zip in TWRP, wipe cache/dalvik, then flash SuperSU and you're good to go the next time an update rolls out. Updating by this method (rooting immedately after flashing update) will also prevent OOS from replacing TWRP with the stock recovery again. When you download the update, you'll know if it's the full zip if the file is >1 GB (they're usually ~1.4 GB,, whereas the partial zips are a few hundred MB).
Unlocked bootloader warning screen is cannot be removed without relocked and fully resetting (wiping) the phone. DM-verity warning screen can be removed by following this guide. Make sure that you are flashing the correct firmware for you current version of OOS though, flashing the wrong version can brick you phone.

Unroot/Relock/revert to stock

Hey everyone,
I'm over rooting. Had an issue today where a backup refused to restore and in trying to fix it, I've deleted my OS. Yes, I'm bad at this. No big deal, I have backups of all my photos and other important stuff.
I don't really want to do the rooting/flashing thing anymore and just want to get my phone back to normal/out of the box as possible so that it will receive regular OTA updates etc. I just want to simplify things.
TWRP is installed. Is it as simple as flashing the latest official update? Or do I need to relock the phone somehow too?
I was going to follow: https://forum.xda-developers.com/oneplus-3t/how-to/guide-to-revert-oneplus-3t-to-stock-t3676210 but wanted to be sure that it would work even though I don't currently have an OS installed.
Thanks!

Southrncomfortjm said:
I'm over rooting. Had an issue today where a backup refused to restore and in trying to fix it, I've deleted my OS.
Click to expand...
Click to collapse
That isn't root. That is your lack of knowledge of the functions of custom recovery, and what the results will be. Better learning and knowledge, and a little more care could have easily prevented it from happening. You wiped the selections in the "Advanced" wipe section of TWRP. And the fact it's called "Advanced" should have been a good clue to not mess with it, unless you know exactly what you are doing.
It's also an easy condition to recover from.
Southrncomfortjm said:
I don't really want to do the rooting/flashing thing anymore and just want to get my phone back to normal/out of the box as possible so that it will receive regular OTA updates etc. I just want to simplify things.
TWRP is installed. Is it as simple as flashing the latest official update? Or do I need to relock the phone somehow too?
I was going to follow: https://forum.xda-developers.com/oneplus-3t/how-to/guide-to-revert-oneplus-3t-to-stock-t3676210 but wanted to be sure that it would work even though I don't currently have an OS installed.
Click to expand...
Click to collapse
That guide is needlessly complicated. Just download the flash the "full" update zip using TWRP, from here: https://forum.xda-developers.com/oneplus-3t/how-to/official-oxygenos-5-0-1-android-8-0-t3728119
Make sure you are using a version of TWRP which supports Oreo (if you were on Oreo when you wiped OS, it should be okay). And that is all there is to it. You will be fully restored to stock, and after rebooting, stock recovery will replace TWRP.
You don't need to lock the bootloader to do this, and you don't need it for future OTAs. But a locked bootloader is arguably more secure, if you really don't need custom recovery or root.
On the other hand, if you still want to give root/phone mods a shot; the way to restore, and still have root is the same (flash full update zip). But just flash Magisk or SuperSU before rebooting, and you will be rooted, and still have TWRP.