Develop Bugs

Stuck at Boot. S-ON.

@4m8 since you are the only guy here who knows best about HTC Desire 300.
Well my friend gave his Desire 300 to me for repair. i thought its going to be easy as like 1,2,3. but guess i was wrong.
I tried several options already.
USB DEBUGGING might be off as well since my friend doesnt know about flashing or unlocking bootloaders. i cant unlock the bootloader i think.
Its S-ON. (Dont know what it actually means).
I tried going to recovery but it shows me a PHONE with A RED ''DOWNLOAD MODE ARROW'' i think recovery is corrupted?
i tried already flashing boot.img and recovery.img over FASTBOOT. but it says ''failed remote signature verify fail''. its just isnt like my sony device which says OKAY all the time lol. those two files were found on a Google drive website.
i have no other options left to revive this phone.
Help will be a very good option :good: thanks in advance.
Well i read a lot of sites which says stuck at boot. and i cant find a Official Stock firmware for this device. is it that HTC didnt released one?

That sounds really bad. So let's recap to see if I understand your situation correctly:
Phone doesn't boot, can't enter recovery and will only load the bootloader. (b-loader status is S-ON Locked)
Now unless you are able to unlock the bootloader (which you aren't as you have stated) there is no way to flash a custom recovery.
The locked bootloader will prevent it because it requires anything you want to flash to be signed by HTC.
The only way out is to flash an actual official update by HTC which afaik is not available for this device.
To make matters worse, if the phone is branded you couldn't even revive it this way because some providers, like mine, actually force HTC
to prevent those phones from flashing an official HTC update that is not branded.
But there is a bright side to your situation. Since you weren't able to unlock the bootloader your friends warenty should still be intact.
And even if this was a branded phone try to claim a replacement from the manufacturer, that way you might have the chance to get
an unbranded device in return for the trouble you and your friend had to endure. :fingers-crossed:
Sorry if I had to shatter the last piece of hope that you were clinging on to but without an unlocked bootloader the only option that
remains is getting a replacement or begging HTC to release an update or the version that is installed by default as a RUU exe
PS:
Just to be certain, you did try the factory reset option in the bootloader before giving up, right?

4m8 said:
That sounds really bad. So let's recap to see if I understand your situation correctly:
Phone doesn't boot, can't enter recovery and will only load the bootloader. (b-loader status is S-ON Locked)
Now unless you are able to unlock the bootloader (which you aren't as you have stated) there is no way to flash a custom recovery.
The locked bootloader will prevent it because it requires anything you want to flash to be signed by HTC.
The only way out is to flash an actual official update by HTC which afaik is not available for this device.
To make matters worse, if the phone is branded you couldn't even revive it this way because some providers, like mine, actually force HTC
to prevent those phones from flashing an official HTC update that is not branded.
But there is a bright side to your situation. Since you weren't able to unlock the bootloader your friends warenty should still be intact.
And even if this was a branded phone try to claim a replacement from the manufacturer, that way you might have the chance to get
an unbranded device in return for the trouble you and your friend had to endure. :fingers-crossed:
Sorry if I had to shatter the last piece of hope that you were clinging on to but without an unlocked bootloader the only option that
remains is getting a replacement or begging HTC to release an update or the version that is installed by default as a RUU exe
PS:
Just to be certain, you did try the factory reset option in the bootloader before giving up, right?
Click to expand...
Click to collapse
Yes i did. Factory reset. But still no luck.
Yes, i cant enter recovery as well.
Well it actually started ones it told me "Process System Not Responding". And on that point i knew the system files are corrupted.
My friend told me, he left the phone in deep sleep after that it didnt turned on again.
Thanks for your help @4m8 :laugh: :good: (IT ISNT MINE SO I DONT HAVE A PROBLEM) I will give this phone back to my friend.
*FACEPALM TO HTC FOR NOT RELEASING A OFFICIAL FIRMWARE*

lollipop OTA fail

Hi guys I got the lollipop OTA for my nexus ( completely stock), never tinkered with it and the OTA installed but now its stuck on "google" screen and constantly bootloops. I have done some reading and I tried to unlock bootloader via Wugfresh toolkit and normal fastboot oem method but no avail, it gets stuck on the "yes" option.
Basically I have a locked bootloader which fails to unlock, and nexus stuck in google logo, any guidance will be much appreciated. Plz point me towards the right direction. :crying:

Try to unlock the bootloader from adb with OEM unlock command. The steps are posted above the factory images on Google's dev site.

yeah I tried that and tablet gets stuck on the yes option at unlock bootloader screen and nothing happens for 20 minutes , i have to restart it. I've read around and it seems like my emmc might have corrupted. Any pointers?

Nxpx said:
yeah I tried that and tablet gets stuck on the yes option at unlock bootloader screen and nothing happens for 20 minutes , i have to restart it. I've read around and it seems like my emmc might have corrupted. Any pointers?
Click to expand...
Click to collapse
Well I can only think of one thing. Buy a new nexus. There aren't any listings for the Wi-Fi version and the LTE on Swappa. However there is some other devices on Swappa.

Softbrick Cyanogenmod

So I'm out of answers currently and would like some help on this one
I installed Cyanogenmod from their website
Installed their rom, recovery
Locked the bootloader since that's what u should do
Today I tried to install a new update from cyanogenmod, it rebooted, and the recovery screen is only showing a black screen and every 5 seconds it will give a white flicker
I tried to unlock the bootloader again but it shows "FAILED (remote: oem unlock is not allowed)"
And I'm not able to get back into android, it will show "ID: xxxxxxxxxxxx" at the bottom and tries to go back into recovery
Help

why did you lock the bootloader when you aren't running the stock rom?
all the modding threads explicitly threads say to avoid doing this otherwise you'll have serious issues.

2x4 said:
why did you lock the bootloader when you aren't running the stock rom?
all the modding threads explicitly threads say to avoid doing this otherwise you'll have serious issues.
Click to expand...
Click to collapse
In all the years of being on xda. I've never seen anyone mention this

wtf... why do use lock bootloader when you arent on stock? You only possibility is to try to get fastboot access to unlock it again...

Relock bootloader without wiping?

Is it possible to relock bootloader without wiping data? All my previous devices didn't require wipe, but I received such strange warning when tried to relock bootloader on Z2 Force Sprint

mapki said:
Is it possible to relock bootloader without wiping data? All my previous devices didn't require wipe, but I received such strange warning when tried to relock bootloader on Z2 Force Sprint
Click to expand...
Click to collapse
I believe you're not able to relock the bootloader until Motorola release a signed bootloader. I had the page once before I'll see if I can find it again and add an edit if I do.

mapki said:
Is it possible to relock bootloader without wiping data? All my previous devices didn't require wipe, but I received such strange warning when tried to relock bootloader on Z2 Force Sprint
Click to expand...
Click to collapse
Don't relock your bootloader unless you want a brick. Technically you can relock it, but everything has to be legit. You've already voided the warranty, relocking won't reinstate that, all that will happen is you'll be bricked with nothing to do about it because you've locked the bootloader.
Why do you want to relock it?

I would like to relock my bootloader and wondering the accuracy of this last post. Will relocking my Sprint Z2 Force bootloader brick my device?
I'm running completely stock via OTA 8.0.0 no root. The reason I want to relock my bootloader is bringing my phone to out of box status and pass SafetyNet. I don't want to root to get this done and I want to continue receiving OTA's.
I understand that my warranty is void when I unlocked bootloader originally and I understand relocking my bootloader will wipe data (factory reset).
Will this brick my phone?
Can I relock anymore?
What are the fastboot commands to relock the Z2?
Thanks!

jeffritz1 said:
I would like to relock my bootloader and wondering the accuracy of this last post. Will relocking my Sprint Z2 Force bootloader brick my device?
I'm running completely stock via OTA 8.0.0 no root. The reason I want to relock my bootloader is bringing my phone to out of box status and pass SafetyNet. I don't want to root to get this done and I want to continue receiving OTA's.
I understand that my warranty is void when I unlocked bootloader originally and I understand relocking my bootloader will wipe data (factory reset).
Will this brick my phone?
Can I relock anymore?
What are the fastboot commands to relock the Z2?
Thanks!
Click to expand...
Click to collapse
I would suggest flashing one of the flash alls for sprint before doing it to ensure being fully stock. The command is below. Also i f you ever have any issues and want to reunlock, you always can with your original unlock code.
"fastboot oem lock"
You'll get a "are you sure" message. Type in the command again and poof, relocked status.

Uzephi said:
I would suggest flashing one of the flash alls for sprint before doing it to ensure being fully stock. The command is below. Also i f you ever have any issues and want to reunlock, you always can with your original unlock code.
"fastboot oem lock"
You'll get a "are you sure" message. Type in the command again and poof, relocked status.
Click to expand...
Click to collapse
So, I did a "fastboot oem lock" and it re locked the bootloader. Restart bootloader, shows locked. Restart phone and still getting a splash screen similar to the one when your unlocked but this time it says "Device has loaded a different Operating System". Continues to boot normally into the system without issues. This was odd so I unlocked again did a Flashall w/ "XT1789-03_NASH_SPRINT_8.0.0_OCXS27.109-48-6_subsidy-DEFAULT_regulatory-DEFAULT_CFC.xml.zip" and "fastboot oem lock". Both times said the lock was successful. But I'm still getting this boot splash screen with test reading "Device has loaded a different Operating System". System boots but still fails SafetyNet.
What gives? What am I missing?

From what I can muster up on XDA I can see that "you need a signed boot.img". Does this mean something and how can I find this?

Can anyone who has unlocked and then relocked their bootloader report on the behavior of your phone? Do you get the same "different OS" splash screen? Has anyone been successful at making it go away and passing safetynet?

jeffritz1 said:
Can anyone who has unlocked and then relocked their bootloader report on the behavior of your phone? Do you get the same "different OS" splash screen? Has anyone been successful at making it go away and passing safetynet?
Click to expand...
Click to collapse
I've been working on this all morning trying a couple different methods. But none have been successful. But the best I can figure, when in bootloader, there is a message stating that your system is "Modified". Somehow, that needs to get changed to what I can only speculate as "unmodified", or something alike.
I tried 3 different versions of returning to stock
First one I tired I cannot seemed to find now
Secondly, I tired:
https://forum.xda-developers.com/z2-force/how-to/how-to-return-to-stock-sprint-t3694783
Posted by Uzephi
I added the command "fastboot oem lock" 2 times just above the fastboot reboot command; thus locking bootloader.
But upon reboot, I still get the modified OS message.
Lastly, I tried this method
https://forum.xda-developers.com/showpost.php?p=76850077&postcount=6
I downloaded https://mirrors.lolinet.com/firmware/moto/nash/official/TMO/XT1789-04_NASH_TMO_C_8.0.0_OCX27.109-36_subsidy-TMO_regulatory-DEFAULT_CFC.xml.zip
Followed the instructions (to some degree) and modified them for Linux since I am not a windows user.
After reboot, radio did not work. No WiFi, not data, nothing. Developer options was already enabled, but oem bootloader unlocking option was grayed out. Now I cannot unlock my bootloader and flash an updated OS.

Thanks for the reply! As of now I am stock latest Sprint 8.0.0 July update with bootloader locked. I get the "Your device has loaded a different Operating System" splash screen when I boot up with a "ID:" followed by nothing. I don't know what this "ID:" with nothing following this means. Also when I run a SafetyNet status app is says failed. But, everything else in the OS appears to be working. Google Play shows "Certified" status and all my apps that require SafetyNet is working (Banking apps, Netflix, Hulu, Google Pay, etc...). So I accomplished my mission in getting these apps working and everything else appears stock. The only thing that troubles me is this "Your device has loaded a different Operating System" splash screen and the failed status in the SafetyNet app. Would love to know how to fix this or an explanation on why.

jeffritz1 said:
Thanks for the reply! As of now I am stock latest Sprint 8.0.0 July update with bootloader locked. I get the "Your device has loaded a different Operating System" splash screen when I boot up with a "ID:" followed by nothing. I don't know what this "ID:" with nothing following this means. Also when I run a SafetyNet status app is says failed. But, everything else in the OS appears to be working. Google Play shows "Certified" status and all my apps that require SafetyNet is working (Banking apps, Netflix, Hulu, Google Pay, etc...). So I accomplished my mission in getting these apps working and everything else appears stock. The only thing that troubles me is this "Your device has loaded a different Operating System" splash screen and the failed status in the SafetyNet app. Would love to know how to fix this or an explanation on why.
Click to expand...
Click to collapse
That message appear because you've unlocked your bootloader before, I'm getting that message too and I can update my device via OTA. If you change that splash screen OTAs will fail.

Marcowe said:
That message appear because you've unlocked your bootloader before, I'm getting that message too and I can update my device via OTA. If you change that splash screen OTAs will fail.
Click to expand...
Click to collapse
Yeah, I was trying to find out if the phone could be reverted back to an out of back state. Another words, no splash screen saying "HEY! I HAVE BEEN MESSED WITH!" like you can on any other phone I have ever owned.
Thanks!

Yes you can
thomas.raines said:
I've been working on this all morning trying a couple different methods. But none have been successful. But the best I can figure, when in bootloader, there is a message stating that your system is "Modified". Somehow, that needs to get changed to what I can only speculate as "unmodified", or something alike.
I tried 3 different versions of returning to stock
First one I tired I cannot seemed to find now
Secondly, I tired:
https://forum.xda-developers.com/z2-force/how-to/how-to-return-to-stock-sprint-t3694783
Posted by Uzephi
I added the command "fastboot oem lock" 2 times just above the fastboot reboot command; thus locking bootloader.
But upon reboot, I still get the modified OS message.
Lastly, I tried this method
https://forum.xda-developers.com/showpost.php?p=76850077&postcount=6
I downloaded https://mirrors.lolinet.com/firmware/moto/nash/official/TMO/XT1789-04_NASH_TMO_C_8.0.0_OCX27.109-36_subsidy-TMO_regulatory-DEFAULT_CFC.xml.zip
Followed the instructions (to some degree) and modified them for Linux since I am not a windows user.
After reboot, radio did not work. No WiFi, not data, nothing. Developer options was already enabled, but oem bootloader unlocking option was grayed out. Now I cannot unlock my bootloader and flash an updated OS.
Click to expand...
Click to collapse
Yes you can , I already had this issue with my moto z2 force in Morocco , so what I did is I connected the phone to internet via bluetooth and when I added my google accounte the unlocking oem in dev option was normal , so I was able to flash roms again . Hope this will help you

I think there is no way to relock bootloader without wipe the device. Also you can relock the bootloader and you will not have any problems. I've already done it, at least with my sprint moto z2 force. the message there is no way to remove it, only flashing a logo.bin, "the boot splash" or replacing the logo.bin of the flash all package by the one of your preference.

EddiePR said:
I think there is no way to relock bootloader without wipe the device. Also you can relock the bootloader and you will not have any problems. I've already done it, at least with my sprint moto z2 force. the message there is no way to remove it, only flashing a logo.bin, "the boot splash" or replacing the logo.bin of the flash all package by the one of your preference.
Click to expand...
Click to collapse
If you do that OTAs will fail

Marcowe said:
If you do that OTAs will fail
Click to expand...
Click to collapse
Yes, you are rigth

So, which of the methods to re-lock did finally work? I was running on Android 8 before, OTA failes for at least 10 times, but suddenly it worked to upgrade to Android 9. Now I am weirdly not passing SafetyNet-check anymore (was working fine on Android 8, GooglePay etc).
Any recommendations? I just need the stupid GPay thing working

How to Lock Bootloader

Hello, I purchased a Pixel 3 XL off craigslist and it is working fine, but the bootloader is unlocked therefore I am receiving a warning when restarting the phone and Google Pay does not work. How can I re-lock the bootloader? Do I need to flash the latest standard google image? The build number is: "crosshatch-userdebug 9 PQ1A.181105.013 5027108 dev-keys". When in bootloader the bootloader version is: b1c1-0.1-5004167. Obviously a n00b here, please be gentle. Thank you for any help.

Do you have a computer? If so what OS do you use?
Sent from my Pixel 3 XL using Tapatalk

superchilpil said:
Do you have a computer? If so what OS do you use?
Sent from my Pixel 3 XL using Tapatalk
Click to expand...
Click to collapse
I do have a computer, a Windows 10 Pro

Are you planning on rooting? If so, you can use Magisk Hide (after using Magisk to root of course) to get Google Pay to work. I would be hesitant to re-lock the BL unless you are certain that it is completely stock otherwise. Re-locking a modified phone can brick the device. Better to just learn how to root, etc and keep it unlocked. You have come to the right place to learn.

sliding_billy said:
Are you planning on rooting? If so, you can use Magisk Hide (after using Magisk to root of course) to get Google Pay to work. I would be hesitant to re-lock the BL unless you are certain that it is completely stock otherwise. Re-locking a modified phone can brick the device. Better to just learn how to root, etc and keep it unlocked. You have come to the right place to learn.
Click to expand...
Click to collapse
No, I don't plan on rooting. But I am afraid of bricking the phone since I don't know what has been done to it. Is there a way to determine what was done to unlock the bootloader? Otherwise I will follow your recommendation of using Magisk Hide. I would prefer to keep the phone stock. Thanks.

eec007 said:
No, I don't plan on rooting. But I am afraid of bricking the phone since I don't know what has been done to it. Is there a way to determine what was done to unlock the bootloader? Otherwise I will follow your recommendation of using Magisk Hide. I would prefer to keep the phone stock. Thanks.
Click to expand...
Click to collapse
If you live in Denver I'll trade you my Verizon one for yours. It has a locked bootloader.

eec007 said:
No, I don't plan on rooting. But I am afraid of bricking the phone since I don't know what has been done to it. Is there a way to determine what was done to unlock the bootloader? Otherwise I will follow your recommendation of using Magisk Hide. I would prefer to keep the phone stock. Thanks.
Click to expand...
Click to collapse
The two obvious things you can check are that you have stock recovery and that the phone is not rooted. Manually power on to bootloader (hold volume down and press power then use the volume keys to select recovery and press power. you should get a no command android screen if in stock recovery. assuming you don't have a Magisk icon, you are probably not rooted but you can confirm by installing and running a root app like root checker. likely, the previous owner did nothing but unlock the BL given how recently it came out, but if someone where really creative they could have done work in the other partition. there are no exploites, so doing it normally (running fastboot flashing unlock from a prompt) is pretty much all that would have been done other than enabling developer options and OEM unlocking in settings.
Personally, I think you have a good chance to learn your device, root (you need to be rooted for Magisk hide) and keep the bootloader unlocked. Besides rooting, being able to install a full factory image instead of an OTA is so much better in my opinion. The amount of work it would take to be 100% confident that the only thing done was the BL unlock would take as much work as at least getting a working knowledge of rooting and reinstalling the OS.
P.S. Keeping a phone "stock and rooted" has advantages. That is how I run my 3 XL and how I ran my OG XL. No custom OS. Not even a kernel.

coolhandz said:
If you live in Denver I'll trade you my Verizon one for yours. It has a locked bootloader.
Click to expand...
Click to collapse
lol, what I don't get is that I thought the google edition could have the bootloader unlocked in the developer options. So why go to this hassle of unlocking the bootloader from fastboot? FYI, in the Developer options the OEM unlocking is greyed out and says "Bootloader is already unlocked".

sliding_billy said:
The two obvious things you can check are that you have stock recovery and that the phone is not rooted. Manually power on to bootloader (hold volume down and press power then use the volume keys to select recovery and press power. you should get a no command android screen if in stock recovery. assuming you don't have a Magisk icon, you are probably not rooted but you can confirm by installing and running a root app like root checker. likely, the previous owner did nothing but unlock the BL given how recently it came out, but if someone where really creative they could have done work in the other partition. there are no exploites, so doing it normally (running fastboot flashing unlock from a prompt) is pretty much all that would have been done other than enabling developer options and OEM unlocking in settings.
Personally, I think you have a good chance to learn your device, root (you need to be rooted for Magisk hide) and keep the bootloader unlocked. Besides rooting, being able to install a full factory image instead of an OTA is so much better in my opinion. The amount of work it would take to be 100% confident that the only thing done was the BL unlock would take as much work as at least getting a working knowledge of rooting and reinstalling the OS.
P.S. Keeping a phone "stock and rooted" has advantages. That is how I run my 3 XL and how I ran my OG XL. No custom OS. Not even a kernel.
Click to expand...
Click to collapse
Thank you! Root Checker says that "root access is not properly installed on this device". The recovery mode screen just has a warning about the bootloader is unlocked and a link to a google help page. I figure that I can always unlock the bootloader again if I need to later, but for now I just want everything to work (bank and pay app) and not worry about updating anything myself. I think I may try fastboot to lock the bootloader for now. Thanks for all the help.

Hope it all works out for you. I assume you did a factory reset on the device since you got it used. Re-locking will do another factory reset.

sliding_billy said:
Hope it all works out for you. I assume you did a factory reset on the device since you got it used. Re-locking will do another factory reset.
Click to expand...
Click to collapse
Yeah, so I locked using "fastboot flashing lock" but then it doesn't start, saying that there is no operating system or something like that. I freaked out and was able to unlock again using "fastboot flashing unlock". Now all is wiped. I guess I need to flash the oem rom first, then lock. I'll have to do this all later tonight. Just glad that I didn't brick it yet.

eec007 said:
Thank you! Root Checker says that "root access is not properly installed on this device". The recovery mode screen just has a warning about the bootloader is unlocked and a link to a google help page. I figure that I can always unlock the bootloader again if I need to later, but for now I just want everything to work (bank and pay app) and not worry about updating anything myself. I think I may try fastboot to lock the bootloader for now. Thanks for all the help.
Click to expand...
Click to collapse
I haven't rooted or bl unlocked in some time now so if I make a mistake someone please correct me. After buying it from a 3rd party I'd wipe the device entirely. Download the correct image and install the latest platform tools for Windows (here) https://developer.android.com/studio/releases/platform-tools and make sure you can connect with adb devices and fastboot devices commands. Then extract the latest full image from here https://developers.google.com/android/images to your platform-tools directory and run the flashall.bat command if you wish to wipe the entire device and get rid of anything the previous owner might have "inadvertently" installed. (this is what I would do but not necessarily what you should do if you want to keep the current apps and system intact) This will reset your device and then you can lock the bootloader with no worry and you'll have a stock system.
I agree that since you can unlock it at any time and you don't need it now then relock it. But there are those here that disagree with me and fight with Magisk and OTAs constantly. But they are not noobs and know what they're doing. If you want to learn there is a wealth of information here so it's your call. Just my 2 cents. But please check my steps before you do anything that might cause issues.
edit: darn, sorry I just saw above that you already tried to lock it. I hope what I said to do will get you out of the predicament.

bobby janow said:
I haven't rooted or bl unlocked in some time now so if I make a mistake someone please correct me. After buying it from a 3rd party I'd wipe the device entirely. Download the correct image and install the latest platform tools for Windows (here) https://developer.android.com/studio/releases/platform-tools and make sure you can connect with adb devices and fastboot devices commands. Then extract the latest full image from here https://developers.google.com/android/images to your platform-tools directory and run the flashall.bat command if you wish to wipe the entire device and get rid of anything the previous owner might have "inadvertently" installed. (this is what I would do but not necessarily what you should do if you want to keep the current apps and system intact) This will reset your device and then you can lock the bootloader with no worry and you'll have a stock system.
I agree that since you can unlock it at any time and you don't need it now then relock it. But there are those here that disagree with me and fight with Magisk and OTAs constantly. But they are not noobs and know what they're doing. If you want to learn there is a wealth of information here so it's your call. Just my 2 cents. But please check my steps before you do anything that might cause issues.
edit: darn, sorry I just saw above that you already tried to lock it. I hope what I said to do will get you out of the predicament.
Click to expand...
Click to collapse
Your steps are basically what I will try tonight. Currently the phone is working again, so there was no harm done yet (just the restore of all apps and such). But I'm going to flash the oem image tonight and start all over again.

eec007 said:
Your steps are basically what I will try tonight. Currently the phone is working again, so there was no harm done yet (just the restore of all apps and such). But I'm going to flash the oem image tonight and start all over again.
Click to expand...
Click to collapse
One thing I would do before I relocked the bl would be to do the full login procedure, email everything other than apps. Then make sure you're on the Nov update in about phone, I'm sure you will be, and then fastboot relock the bl with the proper command. It will wipe the device again but it's a small price to pay for about 10 minutes of work. Then once it reboots and there is no more error message you'll be fully stock. Enable dev options again and make sure the oem switch is active allowing bl unlock. Then you're done. I've gotten to the point on my 5X where I even flip the oem switch so it can't be bl unlocked until I go in and flip it back. Dangerous if you're flashing stuff but not so much if you're just taking OTAs. That's of course your call entirely. Good luck.

eec007 said:
lol, what I don't get is that I thought the google edition could have the bootloader unlocked in the developer options. So why go to this hassle of unlocking the bootloader from fastboot? FYI, in the Developer options the OEM unlocking is greyed out and says "Bootloader is already unlocked".
Click to expand...
Click to collapse
That will stay grayed out until you relock the bootloader. That slider "allows" unlocking. Then you boot into fastboot and unlock it.
So you would reverse the process, hit fastboot and relock the bootloader. Then you can toggle the slider back to not allow unlocking.
Relocking the bootloader will wipe your phone.
You should not do this until you first flash the full factory image to make sure the phone is 100 percent stock. And if it were my phone I would wait for the next OTA update after flashing it back to stock to make sure it goes ok. Then lock it.
And then I would wait awhile before hitting the slider.
You are playing with fire here, if you mess it up and lock it and hit the slider you will not be able to fix it. And no offense, but since you have not done this all before on this phone chances are good you will mess it up.
So, flash to stock and leave it unlocked.
Then wait for the next OTA.
Then lock it.
Then wait a bit more before you hit the slider.
And remember, since you are not the original buyer you will not be able to warranty it.

eec007 said:
Hello, I purchased a Pixel 3 XL off craigslist and it is working fine, but the bootloader is unlocked therefore I am receiving a warning when restarting the phone and Google Pay does not work. How can I re-lock the bootloader? Do I need to flash the latest standard google image? The build number is: "crosshatch-userdebug 9 PQ1A.181105.013 5027108 dev-keys". When in bootloader the bootloader version is: b1c1-0.1-5004167. Obviously a n00b here, please be gentle. Thank you for any help.
Click to expand...
Click to collapse
They're right to mention that relocking a modified device can result in a brick.
Your best bet is to go to https://developers.google.com/android/images#taimen
Follow the directions to the "T", then relock it if you are really really sure that the unlock screen bothers you.
Would suggest to do this anyway, no matter future unlock status.

TonikJDK said:
That will stay grayed out until you relock the bootloader. That slider "allows" unlocking. Then you boot into fastboot and unlock it.
So you would reverse the process, hit fastboot and relock the bootloader. Then you can toggle the slider back to not allow unlocking.
Relocking the bootloader will wipe your phone.
You should not do this until you first flash the full factory image to make sure the phone is 100 percent stock. And if it were my phone I would wait for the next OTA update after flashing it back to stock to make sure it goes ok. Then lock it.
And then I would wait awhile before hitting the slider.
You are playing with fire here, if you mess it up and lock it and hit the slider you will not be able to fix it. And no offense, but since you have not done this all before on this phone chances are good you will mess it up.
So, flash to stock and leave it unlocked.
Then wait for the next OTA.
Then lock it.
Then wait a bit more before you hit the slider.
And remember, since you are not the original buyer you will not be able to warranty it.
Click to expand...
Click to collapse
I agree with most of your post other than waiting for the next OTA before you lock the bootloader. Why would he need to do that? If he's stock, and he'll see that immediately, then relock it. He doesn't want root or Magisk but only wants banking and Pay. With the slider allowing bl unlock he's in no danger whatsoever. Lock and relock whenever he wants. OTA will not disallow the slider once it's set.

TonikJDK said:
That will stay grayed out until you relock the bootloader. That slider "allows" unlocking. Then you boot into fastboot and unlock it.
So you would reverse the process, hit fastboot and relock the bootloader. Then you can toggle the slider back to not allow unlocking.
Relocking the bootloader will wipe your phone.
You should not do this until you first flash the full factory image to make sure the phone is 100 percent stock. And if it were my phone I would wait for the next OTA update after flashing it back to stock to make sure it goes ok. Then lock it.
And then I would wait awhile before hitting the slider.
You are playing with fire here, if you mess it up and lock it and hit the slider you will not be able to fix it. And no offense, but since you have not done this all before on this phone chances are good you will mess it up.
So, flash to stock and leave it unlocked.
Then wait for the next OTA.
Then lock it.
Then wait a bit more before you hit the slider.
And remember, since you are not the original buyer you will not be able to warranty it.
Click to expand...
Click to collapse
Thank you for explaining this. I had thought that the Developer Option slider was to unlock the bootloader, but your explanation clarifies it, the slider is to allow the bootloader to be unlocked...

Ok, so I tried to flash the factory image using adb flash-all and it keeps getting the error:
Sending sparse 'vendor_a' 2/2 (193888 KB) FAILED (Error reading sparse file)
Now the phone is not working at all and says that "device is corrupt" and will not boot past the white google screen. I can try again using adb, but it is the same error each time. I tried to download the image again and same sparse error. I can also fastboot in TWRP, but not sure what to do in there. What am I doing wrong? I guess I should've rooted and used Magisk like others have said.

turns out changing to a different cable resolved my sparse error and I was then successfully able to apply the factory image and lock the device. Thanks everyone for the help.