Develop Bugs

Is an unlocked bootloader a security vulnerability?

I'm not a developer, just an enthusiast. Trying to understand if having an unlocked bootloader causes my device to be vulnerable to fastboot attacks? Or is my devices data still encrypted as long as i have a password? I know booting into my twrp recovery requires my password before decryption.. but can't they just fastboot boot a twrp image and gain access to my data somehow? or no? Can someone with knowledge explain?

If they have your phone in their hand yes it is a risk. They have access to all it's contents.

How hard is it to relock your bootloader? My bootloader is unlocked and my phone was rooted (i seem to have lost my root somehow maybe through an update). I am considering relocking my bootloader so that I can try Android Pay. Is this possible and is there a tutorial?

TolaSkamp said:
How hard is it to relock your bootloader? My bootloader is unlocked and my phone was rooted (i seem to have lost my root somehow maybe through an update). I am considering relocking my bootloader so that I can try Android Pay. Is this possible and is there a tutorial?
Click to expand...
Click to collapse
Of course there are tutorials, tons of them. One quick note, you should flash the latest factory image while you are unlocked to make sure everything is fully stock. No reason to save the data, just use flash-all, since relocking will wipe it all anyway. You could also just flash a kernel such as Elemental to access Android Pay.

bobby janow said:
Of course there are tutorials, tons of them. One quick note, you should flash the latest factory image while you are unlocked to make sure everything is fully stock. No reason to save the data, just use flash-all, since relocking will wipe it all anyway. You could also just flash a kernel such as Elemental to access Android Pay.
Click to expand...
Click to collapse
Thanks for the reply. I will probably just flash the Elemental kernel and leave the bootloader unlocked, thanks. I seem to have lost my root, would I need to be rooted. I really rather not have to wipe all my data.

TolaSkamp said:
Thanks for the reply. I will probably just flash the Elemental kernel and leave the bootloader unlocked, thanks. I seem to have lost my root, would I need to be rooted. I really rather not have to wipe all my data.
Click to expand...
Click to collapse
No need to be rooted. Just boot to twrp and flash the kernel. AP with then work I believe. Try it out, I'm locked so I can't say for sure but on my 5x it works.

Doesn't Android Device Manager (or something there of) have some protection against lost/stolen phones. I recall reading that once you have your Google account sync'ed to the phone, you will need your Google account password to restart the phone even after a factory reset.

robchow said:
Doesn't Android Device Manager (or something there of) have some protection against lost/stolen phones. I recall reading that once you have your Google account sync'ed to the phone, you will need your Google account password to restart the phone even after a factory reset.
Click to expand...
Click to collapse
This is easily bypassed. It will keep the honest people out, but with minimal effort someone could get past it.
Sent from my Pixel XL using Tapatalk

Here is the Android feature I was referring to about needing Google account's password:
Factory Reset Protection (FRP)
https://support.google.com/pixelphone/answer/6172890?hl=en
Am I correct that this statement "If you have Developer options turned on, you can also turn off device protection from your device's Settings app Settings. Tap Developer options and then OEM Unlocking" relates to bootloader unlock? As such, if unlocked bootloader then this FRP isn't active? Can FRP be turned on with unlocked bootloader?
superchilpil said:
This is easily bypassed. It will keep the honest people out, but with minimal effort someone could get past it.
Click to expand...
Click to collapse
Are you suggesting that FRP is easily bypassed?

Verizon Pixel Bootloader

Okay so I just got a replacement on my Verizon Google pixel and after everything was setup I noticed that in the developer options it gave me the option to unlock my Bootloader. I know the Verizon models are locked and after 7.1 the exploit was patched. I have all the Verizon bloatware so is this just a bug or is it possible? I turned off all automatic updates just in case so should I go ahead and try?
youtu.be/yYbhMk4fnLM

The0nlyboss said:
Okay so I just got a replacement on my Verizon Google pixel and after everything was setup I noticed that in the developer options it gave me the option to unlock my Bootloader. I know the Verizon models are locked and after 7.1 the exploit was patched. I have all the Verizon bloatware so is this just a bug or is it possible? I turned off all automatic updates just in case so should I go ahead and try?
youtu.be/yYbhMk4fnLM
Click to expand...
Click to collapse
If you want to try unlocking your bootloader go for it. But there's not much benefit to unlocking your bootloader unless you plan to root or flash a custom rom or custom kernel or something. Simply unlocking the bootloader but otherwise staying fully stock will not allow your phone to pass safety net so you won't be able to use Android Pay. There have been a few other posts from Verizon customers where they got phones with the option to unlock the bootloader enabled so you probably just got lucky.

The0nlyboss said:
Okay so I just got a replacement on my Verizon Google pixel and after everything was setup I noticed that in the developer options it gave me the option to unlock my Bootloader. I know the Verizon models are locked and after 7.1 the exploit was patched. I have all the Verizon bloatware so is this just a bug or is it possible? I turned off all automatic updates just in case so should I go ahead and try?
youtu.be/yYbhMk4fnLM
Click to expand...
Click to collapse
If it was shipped from Carol Stream, Illinois and if you pop in your SIM and the Verizon website calls it a non-VZW phone., then you got a Google Edition. Since OEM unlocking is not grayed out on yours, it's almost for certain a Google Edition. Same happened to me, the bloatware came when the Verizon SIM was inserted.
I agree with the above jhs39 post, though, only do it if you have a reason. I wanted the Pure Nexus ROM and ViPER4Android so I did it.

jhs39 said:
If you want to try unlocking your bootloader go for it. But there's not much benefit to unlocking your bootloader unless you plan to root or flash a custom rom or custom kernel or something. Simply unlocking the bootloader but otherwise staying fully stock will not allow your phone to pass safety net so you won't be able to use Android Pay. There have been a few other posts from Verizon customers where they got phones with the option to unlock the bootloader enabled so you probably just got lucky.
Click to expand...
Click to collapse
I don't have the need for it unlocked now but is it possible that an update can remove the option as I do want to flash a rom in the future.

3aucla1r3 said:
If it was shipped from Carol Stream, Illinois and if you pop in your SIM and the Verizon website calls it a non-VZW phone., then you got a Google Edition. Since OEM unlocking is not grayed out on yours, it's almost for certain a Google Edition. Same happened to me, the bloatware came when the Verizon SIM was inserted.
I agree with the above jhs39 post, though, only do it if you have a reason. I wanted the Pure Nexus ROM and ViPER4Android so I did it.
Click to expand...
Click to collapse
Ah I see. It was shipped from that location and I checked the IMEI on Verizon's website and it says it's not capable for some reason so I'm guessing it's a GE.

The0nlyboss said:
Ah I see. It was shipped from that location and I checked the IMEI on Verizon's website and it says it's not capable for some reason so I'm guessing it's a GE.
Click to expand...
Click to collapse
Yeah but it really is capable, just put the SIM in

If you plan on flashing custom in the future then I would unlock now so you don't have to lose all you're data later. Rather wipe while it's new and doesn't have months of data on it.

You never know when you might get screwed over by an update and or want to flash back a version.
I say unlock to give yourself a few more exit strategies should anything go wrong and if you decide to root and rom at some point later you aren't gonna wipe your device.
If you want to pass safety net for android pay you just need to flash a custom kernel.

The0nlyboss said:
I don't have the need for it unlocked now but is it possible that an update can remove the option as I do want to flash a rom in the future.
Click to expand...
Click to collapse
That's true. But if you use Android Pay or any other apps that require safety net they will stop working unless you flash a custom kernel. If that doesn't matter to you then you should unlock the bootloader while you can.

Should we unlock the Bootloader if no root planned

If you have no plans to root the phone is there any reason to unlock the bootloader?

It would probably break Safety net and Android pay. BUT if you're unlocked, you have ability to flash factory images. That could be beneficial something goes really bad and your device won't boot up. You're also less secure with it unlocked.
Sent from my marlin using XDA Labs

You can always lock and unlock the bootloader when you want.

I would say you should at least have the option checked on in the Developer settings.
So just in case something happened and you can't fully boot the phone. you can still get into it and unlock the bootloader and do what you need to do.
This happened to a friend of mine where something happened and couldn't fully boot and couldn't unlock bootloader cause the option was never checked.

I don't believe the unlock option stays enabled after it boots up.

I would argue why WOULDN'T you unlock the bootloader? Regardless of rooting, an unlocked bootloader is a safety net for when things go south. Phone decides to bootloop tomorrow? No big deal, flash the latest images via fastboot and start from scratch.
Sure there's the counter argument of the phone being much less secure and vulnerable in the hands of a person who is tech savvy and stole/found your device. I'm not worried about my phone being stolen so I ALWAYS unlock my bootloader.

Pain-N-Panic said:
I would argue why WOULDN'T you unlock the bootloader? Regardless of rooting, an unlocked bootloader is a safety net for when things go south. Phone decides to bootloop tomorrow? No big deal, flash the latest images via fastboot and start from scratch.
Sure there's the counter argument of the phone being much less secure and vulnerable in the hands of a person who is tech savvy and stole/found your device. I'm not worried about my phone being stolen so I ALWAYS unlock my bootloader.
Click to expand...
Click to collapse
or just flash the full OTA image without an unlocked bootloader.

mngdew said:
You can always lock and unlock the bootloader when you want.
Click to expand...
Click to collapse
Does re-locking the bootloader wipe the phone?

foosion said:
Does re-locking the bootloader wipe the phone?
Click to expand...
Click to collapse
Yes, it does. That's why you should unlock or lock the bootloader when flashing factory images.

mngdew said:
Yes, it does.
Click to expand...
Click to collapse
Thanks
mngdew said:
That's why you should unlock or lock the bootloader when flashing factory images.
Click to expand...
Click to collapse
I don't understand what you mean by this.
You have to unlock the bootloader to flash a factory image and you can eliminate the w flag so that flashing the factory image won't wipe the phone.

uicnren said:
or just flash the full OTA image without an unlocked bootloader.
Click to expand...
Click to collapse
Very true. If the phone goes into booploop due to a bad zip or whatever other reason you have a bricked device with no options to recover.

It's healthy for me to unlock my Bootloader ASAP on XDA!

Unlocking the bootloader was always the very first thing I did when I got a new phone. However, I use Android Pay all the time, and Google seems very determined to break AP for unlocked bootloaders with every new patch. Sure, someone usually finds a way to get it working again, but that sometimes takes time, and I simply use AP too much to deal with it. As long as AP won't work officially with an unlocked bootloader, mine stays locked unless I'm flashing an image, and even then, gets locked right after. Luckily, OTAs are posted by Google now, often at the same time as the Factory Images, so it hasn't really been an issue for me.

akenis said:
It would probably break Safety net and Android pay. BUT if you're unlocked, you have ability to flash factory images. That could be beneficial something goes really bad and your device won't boot up. You're also less secure with it unlocked.
Sent from my marlin using XDA Labs
Click to expand...
Click to collapse
Thank you what actually is compromised when phone is unlocked?

uicnren said:
or just flash the full OTA image without an unlocked bootloader.
Click to expand...
Click to collapse
How can you flash with a locked bootloader?

painfree said:
Thank you what actually is compromised when phone is unlocked?
Click to expand...
Click to collapse
Data?
https://www.google.com/amp/s/www.ho...unlocking-your-android-phones-bootloader/amp/
Sent from my marlin using XDA Labs

painfree said:
If you have no plans to root the phone is there any reason to unlock the bootloader?
Click to expand...
Click to collapse
If you ever contemplate going onto the Verizon network, when you first boot up after placing VZN sim into the phone,
the ability to ever unlock again is eliminated. You could relock it, but it will have the Unlock option in Developer
Option greyed out forever after that. I would unlock it maybe because of Verizon thing, but also to be able to flash factory a image in case I ever mess up the phone.

michaelbsheldon said:
If you ever contemplate going onto the Verizon network, when you first boot up after placing VZN sim into the phone,
the ability to ever unlock again is eliminated. You could relock it, but it will have the Unlock option in Developer
Option greyed out forever after that. I would unlock it maybe because of Verizon thing, but also to be able to flash factory a image in case I ever mess up the phone.
Click to expand...
Click to collapse
As long as you have the Google version it should never grey out on you at least that's how it was with the first pixels. I have Verizon I've never had it grey out.

jt3 said:
Unlocking the bootloader was always the very first thing I did when I got a new phone. However, I use Android Pay all the time, and Google seems very determined to break AP for unlocked bootloaders with every new patch. Sure, someone usually finds a way to get it working again, but that sometimes takes time, and I simply use AP too much to deal with it. As long as AP won't work officially with an unlocked bootloader, mine stays locked unless I'm flashing an image, and even then, gets locked right after. Luckily, OTAs are posted by Google now, often at the same time as the Factory Images, so it hasn't really been an issue for me.
Click to expand...
Click to collapse
This. Android Pay is pretty convenient and I always told myself I didn't need it compared to unlock+root. Wish Google would allow AP with unlocked bootloader but I can understand why they don't from a security standpoint.
Sent from my Pixel 2 XL using Tapatalk

foosion said:
Thanks
I don't understand what you mean by this.
You have to unlock the bootloader to flash a factory image and you can eliminate the w flag so that flashing the factory image won't wipe the phone.
Click to expand...
Click to collapse
When you unlock the bootloader, phone is wiped automatically.

Relock Verizon Bootloader

I have my Verizon pixel xl unlocked with the sunshine mod from when I first got it. Can I relock the bootloader without the oem unlock setting being greyed out so I can unlock it in the future?

According to jcase, no.
http://theroot.ninja/depixel8.html said:
DO NOT RELOCK YOUR BOOTLOADER, unless you have restored it back to 100% stock and are sure you won't want it unlocked again.
Click to expand...
Click to collapse
Why do you want to relock it anyways?

fiveighteen said:
According to jcase, no.
Why do you want to relock it anyways?
Click to expand...
Click to collapse
While jcase was against it, after I have done my research, I attempted relocking my Verizon bootloader so I could send it out for RMA. I did it after I flashed the original factory image and made sure everything is back to OEM. So, I can tell you that it is possible. However, PLEASE don't take my words for it. Do your research and be 110% sure before you proceed. My heart was pounding so hard when I was trying to relock it because of the uncertainty... Anyway, do it at your own risk, I am just sharing you my experience, but please don't blame me if things go south

andrep182 said:
While jcase was against it, after I have done my research, I attempted relocking my Verizon bootloader so I could send it out for RMA. I did it after I flashed the original factory image and made sure everything is back to OEM. So, I can tell you that it is possible. However, PLEASE don't take my words for it. Do your research and be 110% sure before you proceed. My heart was pounding so hard when I was trying to relock it because of the uncertainty... Anyway, do it at your own risk, I am just sharing you my experience, but please don't blame me if things go south
Click to expand...
Click to collapse
Did you hit the slider too?
Were you able to unlock it again...if you tried?
Just curious and gathering info.....

TonikJDK said:
Did you hit the slider too?
Were you able to unlock it again...if you tried?
Just curious and gathering info.....
Click to expand...
Click to collapse
If by slider, you meant to ask if I locked it again, yes I did. I believe I relock it through fastboot.
There was really no point for me to unlock it again because I needed to send it for RMA so I never tried.

TonikJDK said:
Did you hit the slider too?
Were you able to unlock it again...if you tried?
Just curious and gathering info.....
Click to expand...
Click to collapse
If you unlock it and your already updated you won't be able to unlock again.

Haven't personally tried but I would be willing to bet a large sum of money if you relock it you will not be able to unlock it again I wouldn't even take the risk.

znel52 said:
Haven't personally tried but I would be willing to bet a large sum of money if you relock it you will not be able to unlock it again I wouldn't even take the risk.
Click to expand...
Click to collapse
I made the mistake of relocking and taking new updates. For sure, the unlock option was removed:
in first step of unlocking phone, the slider in Dev Options was forever greyed out. And it did not understand
fastboot unlock commands again. I would not recommend relocking Pixels for any reason other than return for
warranty repair.

michaelbsheldon said:
I made the mistake of relocking and taking new updates. For sure, the unlock option was removed:
in first step of unlocking phone, the slider in Dev Options was forever greyed out. And it did not understand
fastboot unlock commands again. I would not recommend relocking Pixels for any reason other than return for
warranty repair.
Click to expand...
Click to collapse
Locking on anything stock past 7.1 without root, would prohibit you from unlocking. If locking your BL + and no root capability = NO ability to unlock BL Thus what we have have So far, no known exploits...at least by me.

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.
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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.
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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.