Develop Bugs

Help with rooting Htc M8 marshmallow

Hi,
So I'm new to these forums and have been browsing all of the rooting guides for my HTC M8. I am running official Marshmallow and really want to root my phone (again) as far I know I have unlocked boot loader. I had to factory reset my phone last year and never got round to re rooting, but now with marshmallow I wish to do so again.
My issue is I can't seem to understand the steps the guides are outlining. I download the links and try and open them, but nothing happens. Is there a step by step fluid guide in rooting my phone? As all the guides I have found have basically blown over my head. I used a toolkit in the past which did everything for me automatically. If no such post exists would someone be able to explain the steps in a simplified manner? (If possible)
Many thanks in advance to any who help

Optcpsi said:
as far I know I have unlocked boot loader
Click to expand...
Click to collapse
This is easy to determine definitely. Boot into bootloader (if you don't know how, ask and I'll explain) and it will either say bootloader is: LOCKED, UNLOCKED or RELOCKED near the top of the screen.
Vomer's guide is dated at this point, but mostly still accurate for what you want to do (root MM); and its the best guide I know of: http://forum.xda-developers.com/htc-one-m8/general/vomerguides-m8-bootldr-unlock-s-off-t2800727
If your bootloader is UNLOCKED, you can skip the whole section on unlocking it, and pick back up the guide again where it says CUSTOM RECOVERY. If the bootloader is LOCKED or RELOCKED, you'll need to do the section for unlocking the bootloader.
AFAIK, the only part of Steps 0 and 1 that is out of date, is the TWRP version. For MM, you should use TWRP 3.0. And somewhat obviously, the fastboot command to flash TWRP will need to have the corresponding file name; rather than the old version number given in the guide's example.
You'll also want to use SuperSU 2.76 (if the SuperSU version is too old, it will fail to root MM and leave you stuck with no boot). But the guide is already rigged to link to the latest stable version (not a particular version number), so presently it already links to 2.76.
Don't continue to Step 2 of the guide. Its not longer accurate, and not needed for root.

redpoint73 said:
This is easy to determine definitely. Boot into bootloader (if you don't know how, ask and I'll explain) and it will either say bootloader is: LOCKED, UNLOCKED or RELOCKED near the top of the screen.
Vomer's guide is dated at this point, but mostly still accurate for what you want to do (root MM); and its the best guide I know of: http://forum.xda-developers.com/htc-one-m8/general/vomerguides-m8-bootldr-unlock-s-off-t2800727
If your bootloader is UNLOCKED, you can skip the whole section on unlocking it, and pick back up the guide again where it says CUSTOM RECOVERY. If the bootloader is LOCKED or RELOCKED, you'll need to do the section for unlocking the bootloader.
AFAIK, the only part of Steps 0 and 1 that is out of date, is the TWRP version. For MM, you should use TWRP 3.0. And somewhat obviously, the fastboot command to flash TWRP will need to have the corresponding file name; rather than the old version number given in the guide's example.
You'll also want to use SuperSU 2.76 (if the SuperSU version is too old, it will fail to root MM and leave you stuck with no boot). But the guide is already rigged to link to the latest stable version (not a particular version number), so presently it already links to 2.76.
Don't continue to Step 2 of the guide. Its not longer accurate, and not needed for root.
Click to expand...
Click to collapse
Thanks for posting, couldn't find an up-to-date tutorial anywhere.
TWRP is asking to keep system read-only and I'm confused. If I allow modificaions, can I automatically never receive OTA updates again?
Will there even be another one for the M8/ will it get Nougat? Anyways, can I still root it with read-only?

Schmix said:
Thanks for posting, couldn't find an up-to-date tutorial anywhere.
TWRP is asking to keep system read-only and I'm confused. If I allow modificaions, can I automatically never receive OTA updates again?
Will there even be another one for the M8/ will it get Nougat? Anyways, can I still root it with read-only?
Click to expand...
Click to collapse
You need to allow modifications for root. At least traditional root. Systemless root, I would think would work if you stay read only - but do the research especially if you don't know the difference between traditional root and systemless root.
You can't install OTA updates with a rooted device in any case, so that point is irrelevant.
If/when ever an OTA comes, you would need to return to stock never rooted ROM and stock recovery, in order to OTA update (there are guides on this forum). This would remove any modification by TWRP.
But that's mostly just FYI/academic. Its extremely unlikely we'll get an OTA update to Nougat. Your best bet for Nougat will be custom ROMs, anyway.

1. UNLOCK bootloader with HTC Dev site.
2. Flash latest twrp recovery
3. Flash Stable v2.65 SuperSU
4. Flash wp mod.
5. Update SuperSU on Play Store.
Latest SuperSU 2.76 zip kills Boomsound. Permissive zip can fix that.

AT&T V410 Root Idea

Hey everyone,
I apologize in advance if this is breaking any forum rules or if it's a super noob question, but here goes.
I've got a stock AT&T V410 running Lollipop (had I known it would be such a hassle to root, I would've stayed on KitKat).
It's no longer under warranty so I'm thinking about rooting. Unfortunately, the only option that might work is KingRoot. Taking into consideration the possible "shadiness" of KingRoot, here is my idea:
1) Remove microSD and factory reset my V410. This is to have as little info on my V410 as possible before running KingRoot. If I can, I'll even skip adding my Google account.
2) Run KingRoot and see if the root is successful.
3) If successful, install Flashify and flash TWRP (which version should I flash?)
4) If not successful, do another factory reset and continue using my V410 like before.
5) After successfully flashing TWRP, I'll probably do another factory reset, if necessary, to have a clean OS without KingRoot.
6) With TWRP installed, I should be able to make a backup of my current V410 OS, right? I'd like to have this in case I try out CM and want to go back.
I think that's it. Assuming KingRoot can root my V410, does everything here seem viable? I know when I unlocked the bootloader on my OPO it basically did a factory reset anyway, but I want to be safe with KingRoot.
TL;DR
Will a factory reset remove KingRoot? Can I install TWRP and keep the original LG OS?

Won't work. The lollipop bootloader can't be unlocked, and I'm not aware of any exploits. TWRP won't boot. Stay on the lollipop bootloader and you're stuck with kingroot, stock rom, and stock recovery to the best of my knowledge.
I have heard of some methods to try to swap kingroot for supersu once you gain root, but I've also heard of that making a colossal mess with this tablet. Never dug into it, but I suspect supersu attempts to patch the boot image, messes up the signature, then the tab won't boot due to the locked bootloader.
The kitkat bootloader was locked too, but it was susceptible to the bump exploit that let us sign our own boot images.
If you're interested in TWRP and custom roms there is a route to downgrade back to the kitkat bootloader, but it sounds like a giant hassle.
Another random thought, there is a way to enable fastboot on this tablet (you would need root to do it). This method is for the LG G2, but it works fine on my V410. Maybe you could extract the partition images from the kdz in that thread linked above and flash them manually with fastboot instead of LG Flashtool, and get back to kitkat without making such a mess of the internal storage. Disclaimer: I haven't tried this and it could end poorly!!! :silly:

jason2678 said:
Won't work. The lollipop bootloader can't be unlocked, and I'm not aware of any exploits. TWRP won't boot. Stay on the lollipop bootloader and you're stuck with kingroot, stock rom, and stock recovery to the best of my knowledge.
I have heard of some methods to try to swap kingroot for supersu once you gain root, but I've also heard of that making a colossal mess with this tablet. Never dug into it, but I suspect supersu attempts to patch the boot image, messes up the signature, then the tab won't boot due to the locked bootloader.
The kitkat bootloader was locked too, but it was susceptible to the bump exploit that let us sign our own boot images.
If you're interested in TWRP and custom roms there is a route to downgrade back to the kitkat bootloader, but it sounds like a giant hassle.
Another random thought, there is a way to enable fastboot on this tablet (you would need root to do it). This method is for the LG G2, but it works fine on my V410. Maybe you could extract the partition images from the kdz in that thread linked above and flash them manually with fastboot instead of LG Flashtool, and get back to kitkat without making such a mess of the internal storage. Disclaimer: I haven't tried this and it could end poorly!!! :silly:
Click to expand...
Click to collapse
Thanks for the reply jason2678
Good to know that even if I could root my V410, I wouldn't be able to unlock the bootloader, which is my whole reason for rooting. And yeah, current methods to downgrade to KitKat seems like a real pain; for the time being it seems like I shouldn't mess with what works

Help with a boot problem. (soft brick?)

Hi.
I recently got a HTC one M8 second hand from my father.
I decided that i wanted my next phone to be rooted, so i started working on that before anything else.
I have followed a youtube guide located at /watch?v=wpFpmAQa-40 (new user, cant post links) to get my phone rooted.
Unlocking the bootloader went fine, and i managed to boot into the OS from then on and managed to make a back-up with TWRP while unrooted.
Getting into the OS with the bootloader unlocked, i downloaded SuperSU-v2.37 onto the phone.
However, once i tried to use TWRP to install this it went wrong.
After installing this, the phone would no longer boot, and get stuck on the initial white boot screen with the HTC logo.
i tried to restore the backup i made using TWRP, but to no anvil.
The bootloader shows *** Software status: Modified *** at the top.
I suspect that becaus this flag is set, the OS reuses to load.
Some more info: the phone in question is from Vodafone, and i used the AT&T/T-Mobile/international TWRP recovery from the site mentioned in the above youtube video at link (site here)/cwmtwrp-recoveries/ (again, new user, can't post links).
As such, it had a bunch of vodafone stuff (like a vodafone boot and shutdown animation), so i also suspect it has some form of carier lock, though i have not been able to find a guide which mentions a vodafone lock, only AT&T, Verison and Sprint.
I someone know how to get my phone working again (preferably rooted, but at this point i would also settle for unrooted, locked and s-on).
I don't really want to go messing with s-off since i aparently already borked this up.
EDIT:
OK, so i tried to do a restore again, seems that restoring does indeed work, but getting SuperSU does not.
I'l look for a more up to date version of superSU.
EDIT2:
It went even wierder now. I can no longer download files on the phone, nor can i transfer files from the computer.
EDIT 3:
Well, didn't fix it, but got aound it. got an sd card in the phone, downloaded SuperSU from the site, and installed it with TWRP from the sd card. access to the internal storage is still blocked/buggy.

First! - The flag ****MODIFIED**** shows when you have custom recovery
and second - in my opinion the best thing you can do is to lock the bootloader using "fastboot oem lock" when in bootloader and then instantly reflash the phone using RUU which should be the Vodaphone version and then use KingoRoot to gain root. Use the PC Root method!

wild_dog said:
I have followed a youtube guide located at /watch?v=wpFpmAQa-40 (new user, cant post links) to get my phone rooted.
Unlocking the bootloader went fine, and i managed to boot into the OS from then on and managed to make a back-up with TWRP while unrooted.
Getting into the OS with the bootloader unlocked, i downloaded SuperSU-v2.37 onto the phone.
However, once i tried to use TWRP to install this it went wrong.
After installing this, the phone would no longer boot, and get stuck on the initial white boot screen with the HTC logo.
Click to expand...
Click to collapse
That Youtube guide is outdated. Its says published Feb 2016, but I thinks that is misleading. I believe the video was made much longer ago. The phone being used has KitKat OS version from the M8 release back in May 2014. And as such, the root method is just as horribly outdated.
If your phone was on Marshmallow OS version, the general process in the video is okay, but you need should use TWRP 3.0.2 and a relatively current stable version SuperSU (which is currently 2.78, that's right 41 versions newer than what you used). TWRP version and SuperSU version is dependent on OS version, but what I"ve stated probably applies to most folks at this point (since Marshmallow was released some time ago, Dec 2015).
Using outdated SuperSU version is the most common reason for no boot after trying to root. And flashing the proper version SuperSU is the fix. So good work figuring it out.
---------- Post added at 11:05 AM ---------- Previous post was at 11:00 AM ----------
wild_dog said:
The bootloader shows *** Software status: Modified *** at the top.
I suspect that becaus this flag is set, the OS reuses to load.
Click to expand...
Click to collapse
This would be an incorrect assertion. Software: Modified has no bearing (in itself) on whether the phone boots into OS or not. As another mentioned, it just means a custom recovery is installed, and/or system modifications (root, etc.) have occurred.
---------- Post added at 11:07 AM ---------- Previous post was at 11:05 AM ----------
wild_dog said:
i tried to restore the backup i made using TWRP, but to no anvil.
EDIT:
OK, so i tried to do a restore again, seems that restoring does indeed work, but getting SuperSU does not.
Click to expand...
Click to collapse
Also, nice work (honestly) making a TWRP backup before trying root. Many folks skip this simple (yet critical) step, and then are in a panic on how to recovery after a failed root attempt.
---------- Post added at 11:10 AM ---------- Previous post was at 11:07 AM ----------
todorkaravalchev said:
in my opinion the best thing you can do is to lock the bootloader using "fastboot oem lock" when in bootloader and then instantly reflash the phone using RUU which should be the Vodaphone version and then use KingoRoot to gain root. Use the PC Root method!
Click to expand...
Click to collapse
While technically valid, this is overly complicated solution; considering the fix was to flash the proper version SuperSU (and bootloader already unlocked, and TWRP installed).
Also, while kingroot works for some folks, others have had issues with it. Rooting with the more common method (TWRP and SuperSU) virtually always works, as long as the proper version SuperSU is used.
Just some constructive comments. Your contribution is appreciated nonetheless.

Yes mate, I agree, but he only wants root and everithing else to work, so, as he said he isn't so good at this things and I offered the purest and easiest way for him to aquire what he wants. Thank you!

And i apriciate the help, todor.
Although i have gotten this working, i have run into some small things (don't you always... SIGH).
I have not gotten the block on coppying files to the internal memmory fixed yet, but for what i wanted to do (remove factory deafault bloatware) it apears i have to do s-off anyway, and i suspect doing so will fix it.
So that will be a nice project for next weekend.
I do have to point out though, that king root, which you referenced, in a listing i found, currently does not support the HTC one M8 with android 6.0, which i have.

wild_dog said:
I have not gotten the block on coppying files to the internal memmory fixed yet
Click to expand...
Click to collapse
This may be a matter of internal storage being corrupted. In TWRP, try going to WIPE, select "Format data" and see if that helps.
Obviously, you will lose your data, so backup before hand, accordingly.
wild_dog said:
but for what i wanted to do (remove factory deafault bloatware) it apears i have to do s-off anyway, and i suspect doing so will fix it.
Click to expand...
Click to collapse
Incorrect, you don't need s-off to delete bloat apps. The issue is that the system is write protected (from deleting bloat apps, etc.) on this device, even with root. You need the kernel mod to disable write protection, in order to delete bloatware.
The wp_mod zip attached to the following thread should work on most or all Android 6 Sense 7 ROMs. But backup your current ROM in TWRP before flashing, just in case it doesn't work properly:
http://forum.xda-developers.com/htc-one-m8/development/rom-stock-unlocked-developer-sense-7-t3262894

I'm not so sure about what I'm about to say, but if you have root and use this file manager called "Root Browser" you should be able to delete the bloat. The only thing that you have to do before you delete something is to mount the /system partition -rw (read, write) and there was such option tn the file manager that I told you about. And make sure you have busybox installed for this option to work.

Help! Bootloop Nightmare!

I was trying to root/custom rom/etc in a hurry and I was interrupted a million times, so I screwed up. SM-N910v. I started out on kitkat, 4.4.1. I tried this guide: https://forum.xda-developers.com/no...t/howto-bootloader-unlock-upgrade-to-t3398144
I odin N910VVRU2BPA1_N910VVRU2CPD1_FullFirmware.tar.md5. That upgraded me lollipop 5.5.1. I then follow a guide similiar to this: https://forum.xda-developers.com/no...asy-guide-how-to-root-verizon-galaxy-t3454593
Its not the exact one, but there is several guides that are the same. I temporary rooted with kingoroot, installed TWRP. One of the guides said not to let it boot normally, so I freaked out and made sure I didn't do that. I booted back into twrp. Using this guide: https://forum.xda-developers.com/note-4-verizon/development/cyanogenmod-t3253973
I can't remember or find the exact guide I was on... But I flashed these files in the following order:
BETA-SuperSU-v2.71-20160331103524.zip
Emotion-TW-5.1.1-nightly-r21-RC1-SM-N910P.zip (this was really dumb)
cm-13.0-20160919-UNOFFICIAL-trltevzw.zip
I tried to boot, I left it on for atleast 30 mins, and the clockworkmod logo kept animating abnormally fast.
I then installed N910VVRU2BPA1_N910VVRU2CPD1_FullFirmware.tar.md5 again (... doh ...).
Now it bootloops.... so I said.. 'ok, maybe I just need my TWRP recovery back'. Tried to install TWRP and fail....
I can boot into safe mode fine, but not normal mode. The problem with safe mode is you can't install apps.
I've tried factory reset, wipe cache, dalvik, etc etc. Nothing. I've also tried a different firmware I believe as well.. I am lost...
Current Android Info:
5.1.1
security patch level: 2015-12-01
baseband version: N910VVRU2CPD1
Kernel version: 3.10.40 Jan 20 2016
Build Number: LMY47X.N910VVRU2BPA1
The information above indicates that I am still in this version: N910VVRU2BPA1_N910VVRU2CPD1_FullFirmware.tar.md5
Ok so.. I just odin this file N910VVRU2BPA1_N910VVZW2BPA1_N910VVRU2BPA1_HOME.tar.md5
Same story, I can boot into normal mode, but not safe mode.
I check my info:
5.1.1
security patch level: 2015-12-01
baseband version: N910VVRU2BPA1
Kernel version: 3.10.40 Jan 20 2016
Build Number: LMY47X.N910VVRU2BPA1
Factory reseting now... and seeing if that fixes my problem... nope... same bootloop problem...
my thinking is... if I undo "samsung_unlock_n4-fix" and that would fix my bootloop. If thats true..... I guess my biggest question is: if the boot loader is unlocked, then why can't I flash TWRP like I was able to the first time??
I appologize, I will be unaviable for the next 5 or 6 days..... any help would be much appreciated!

I followed Max Lee's guide on youtube for rooting/unlocking the bootloader I recommend downloading the files he has linked, just ensure that your phone is the SM-N910V the hardest part or more time consuming part is getting kingo root to get you that temporary root needed to unlock your bootloader/root phone. Kingo root is very unstable and your phone will freeze/restart many times, You definitely need a spare sd card, at least a 2GB from my experience and patience, set aside a few hours because your follow through is crucial. If all goes well you will be able to install TWRP. I hope this helps. Tip, if you decide to follow his method, the file titled 'samsung_unlock_n4-2' you need to rename it to say 'samsung_unlock_n4-fix' good luck!

UmbrellaTakedown said:
I followed Max Lee's guide on youtube for rooting/unlocking the bootloader I recommend downloading the files he has linked, just ensure that your phone is the SM-N910V the hardest part or more time consuming part is getting kingo root to get you that temporary root needed to unlock your bootloader/root phone. Kingo root is very unstable and your phone will freeze/restart many times, You definitely need a spare sd card, at least a 2GB from my experience and patience, set aside a few hours because your follow through is crucial. If all goes well you will be able to install TWRP. I hope this helps. Tip, if you decide to follow his method, the file titled 'samsung_unlock_n4-2' you need to rename it to say 'samsung_unlock_n4-fix' good luck!
Click to expand...
Click to collapse
I appreciate your post. However I don't think you quite understand whats going on.
https://galaxynote4root.com/cwmtwrp-recovery/
His site specifically states: "Verizon SM-N910V unless you have a developer’s edition phone as retail version come with locked bootloaders meaning you cannot install regular CWM or TWRP!!!"
It also shows that comment in the video. I definitely DO NOT have the developers edition.
In summary: I flashed the firmware that has the bootloader unlock vulnerability->Installed twrp->Installed CWM->Installed Firmware with bootloader vulnerability, which replaced everything I did. Now it seems like the bootloader is re-locked, and I can't boot into normal mode, which means I can't run kingo again. I can't flash TWRP, the only things I can do are: adb sideload, odin, boot any 5.1.1 in safe mode.

TouchOdeath said:
I appreciate your post. However I don't think you quite understand whats going on.
https://galaxynote4root.com/cwmtwrp-recovery/
His site specifically states: "Verizon SM-N910V unless you have a developer’s edition phone as retail version come with locked bootloaders meaning you cannot install regular CWM or TWRP!!!"
It also shows that comment in the video. I definitely DO NOT have the developers edition.
In summary: I flashed the firmware that has the bootloader unlock vulnerability->Installed twrp->Installed CWM->Installed Firmware with bootloader vulnerability, which replaced everything I did. Now it seems like the bootloader is re-locked, and I can't boot into normal mode, which means I can't run kingo again. I can't flash TWRP, the only things I can do are: adb sideload, odin, boot any 5.1.1 in safe mode.
Click to expand...
Click to collapse
I did not have a developers edition either, I have retail, this method makes your phone into the developer edition. This method is designed for verizons note 4. So what i'm saying is, I followed his method using a retail note 4 branded verizon and this exploit makes it into a developers edition so you may install twrp and roms. You are able to odin flash stock firmware for marshmallow and then downgrade to 5.1 to run max's method.

Ok so.. I managed to get everything working... so I'm happy. Thank you UmbrellaTakedown for invoking thought and thank you for replying, your the only person who replied, so much appreciated!
1. Boot into safe mode
2. Install app by: adb install c:\kingoroot.apk
3. At this point, its installed but the launcher needs to be refreshed for the icon to show up. I don't know how to refresh the launcher without a reboot.. so...
4. Find the kingoroot package name: adb shell 'pm list packages -f'
5. In my case it said: package:/data/app/com.kingo.root-1/base.apk=com.kingo.root So your answer is: com.kingo.root
6. Now in order to launch kingo, you need to find the activity of the package: adb shell pm dump PACKAGE_NAME | grep -A 1 MAIN
7. Start the activity: adb shell am start -n com.kingo.root/com.kingoapp.root.MainActivity
From here I was able to temp root through kingo, and run samsung_unlock_n4-fix. This time I had to only run samsung_unlock_n4-fix once. After that, TWRP installed no problem (where before it would not).
Update:
I am now officially on Jasmine ROM marshmallow. I had to copy the jasmine folder to /data/media/0/TWRP/BACKUPS/xxxx/jasmine
xxxx= you get that from adb devices
Then simply do a restore, after restore, restore the partial firmware file (it has to be done in that order or else it won't work)

TouchOdeath said:
Ok so.. I managed to get everything working... so I'm happy. Thank you UmbrellaTakedown for invoking thought and thank you for replying, your the only person who replied, so much appreciated!
1. Boot into safe mode
2. Install app by: adb install c:\kingoroot.apk
3. At this point, its installed but the launcher needs to be refreshed for the icon to show up. I don't know how to refresh the launcher without a reboot.. so...
4. Find the kingoroot package name: adb shell 'pm list packages -f'
5. In my case it said: package:/data/app/com.kingo.root-1/base.apk=com.kingo.root So your answer is: com.kingo.root
6. Now in order to launch kingo, you need to find the activity of the package: adb shell pm dump PACKAGE_NAME | grep -A 1 MAIN
7. Start the activity: adb shell am start -n com.kingo.root/com.kingoapp.root.MainActivity
From here I was able to temp root through kingo, and run samsung_unlock_n4-fix. This time I had to only run samsung_unlock_n4-fix once. After that, TWRP installed no problem (where before it would not).
Update:
I am now officially on Jasmine ROM marshmallow. I had to copy the jasmine folder to /data/media/0/TWRP/BACKUPS/xxxx/jasmine
xxxx= you get that from adb devices
Then simply do a restore, after restore, restore the partial firmware file (it has to be done in that order or else it won't work)
Click to expand...
Click to collapse
Just an FYI, you need to run the sasmung_unlock_n4 application twice. The first time, it will write your eMMC CID to the correct one, and the second time you execute, it will write the CID signature/blob to the bootloader - completing the unlock process. Glad to see you got it working.

is my phone really rooted?

I used to be more active on these forums before I got my oneplus 5T and one of the biggest reasons was I wanted a clean fast OS without all the bloatware that many other manufacturers put on their phones. I tried a search but I did not find what I was looking for, so I apologize in advance if this is already covered in another thread.
Anyway, I picked up a 5T about a year ago while visiting family in Europe. (I'm the 2nd owner to the phone) I never bothered to install TWRP or anything else bcs the phone was running really well with stock. All OTA updates have been installing whenever they were released.
Now to my question. While trying to install workspace one app from playstore (my company requires it) the app won't install bcs it claims my phone is rooted. That is the only app that I have ever had any issues with.
I ran root check witch states "sorry! Root access is not properly installed on this device"
How do I unroot my phone if it's really rooted? Or lock the bootloader? maybe that's the same? TWRP is not installed, when I boot into recovery I get into oneplus stock recovery software.

Hi, unfortunately I can't tell you right off if your phone is rooted. If root checker is saying no, then maybe you aren't, but still check if you have magisk or some other root solution app installed. When you got it from someone, they also could have flashed ROMs etc and when they returned it to stock for resale, they night have missed something like relocking bootloader, even if they did re install stock recovery. If I were in your shoes though, I would reboot to bootloader and check if it's unlocked or not. If it is, it's a simple "fastboot oem lock" from terminal. If that's not the case or solution, I dunno what to say. One thing that I would do if I were desparate is to try to take a backup of all the music/pics/texts/whatever other essential bits of data. Then I would reinstall stock recovery, as well as the latest official (not beta) Oxygen OS from oneplus's page. You can find it under the support tab and then software upgrade, then choose the device. Not only that but maybe completely nuke it, as in format, wipe, etc. And lock the bootloader and also let it get encrypted and stuff.. in other words, restore to as stock as possible. Then once you are done you can test. If this fails and bricks, there's a unbrick guide somewhere here for our phone, and also the backup is there for you. If you successfully restore to stock and this does not work, then maybe it is just the app that has a problem with not super stock Android (OOS). I must warn you that this process is risky and I am in no way gonna be responsible for lost data, because I did say make a backup and also it is up to you to do this. I hope this helps a bit, and if you aren't super familiar with the process it may take a while, around an hour if you do not run into any hitches and your download speed is good enough.