How To Guide [GUIDE] Pixel 5a "barbet": Unlock Bootloader, Update, Root, Pass SafetyNet

[V0latyle]

Just in case sharing a tip for a situation I have encountered multiple times while building and testing TWRP boot.img,
This will happen if you try to boot any broken(corrupted) unbootable boot.img.
Fastboot sends the image to device and bootloader reports with unsupported. You reboot and phone goes straight to recovery with 2 options - try again or wipe data. You can't boot to Android keeping data any more despite the fact that you didn't flash anything and boot_a/b partitions are still good. In that case the only way out is to do "fastboot boot <known good boot.img>" and then do normal reboot with no lost of data.
Hope this never happens, but now you know if it does...

TWRP hasn't been updated to work with Android 12 yet. Nor has this been a concern in tis context. Please don't post solutions to problems that are not relevant here, as they can be confusing to some users.

But yes, in all circumstances, if there is a problem with the patched boot image, the user can always reflash the factory boot image.

 

[nijel8]

TWRP hasn't been updated to work with Android 12 yet. Nor has this been a concern in tis context. Please don't post solutions to problems that are not relevant here, as they can be confusing to some users.

But yes, in all circumstances, if there is a problem with the patched boot image, the user can always reflash the factory boot image.

TWRP works just fine with Android 12 and what I posted can happen to everyone patching the boot.img... You should know better files get corrupted all the time...
And I am not even tallking about flashing... Just booting bad boot.img puts the phone in wipe-data state.

 

[V0latyle]

TWRP works just fine with Android 12 and what I posted can happen to everyone patching the boot.img... You should know better files get corrupted all the time...
And I am not even tallking about flashing... Just booting bad boot.img puts the phone in wipe-data state.

Not always, the bootloader will generally reject the boot image altogether, due to dm-verity.

TWRP does not work with Android 12 on the 765G platforms. It won't decrypt data, and in my case on the Pixel 5, gets stuck at the TWRP loading screen.

 

[GrandAdmiral]

So I am trying to install the latest update using the OTA option (already on Android 12 using the same process), but the system update screen keeps tells me that it can't install the update (message says "Installation problem"). I'm currently plugged up and the battery is over 50% charged. Anyone encounter this before?

 

[V0latyle]

So I am trying to install the latest update using the OTA option (already on Android 12 using the same process), but the system update screen keeps tells me that it can't install the update (message says "Installation problem"). I'm currently plugged up and the battery is over 50% charged. Anyone encounter this before?

Yes, sometimes this occurs on rooted devices. Keep trying, or use a different method.

 

[Jeroen1000]

@V0latyle Maybe I am doing it wrong on my 5a but I end up on the same SW-version as before my upgrade. I may assume wrongly here your instructions can also be applied to the Pixel 5a. Can you please offer your insights?

Device is on 12.0.0 (SQ1A.211205.008, Dec 2021) and going to 12.0.0 (SQ1A.220105.002, Jan 2022)

@Oswald Boelcke Apologies for posting in the wrong forum. I had (obviously) not checked there was a similar topic here. It does appear @V0latyle answer got lost: I got an e-mail that he replied but the reply cannot be found

 

[V0latyle]

@V0latyle Maybe I am doing it wrong on my 5a but I end up on the same SW-version as before my upgrade. I may assume wrongly here your instructions can also be applied to the Pixel 5a. Can you please offer your insights?

Device is on 12.0.0 (SQ1A.211205.008, Dec 2021) and going to 12.0.0 (SQ1A.220105.002, Jan 2022)
View attachment 5507707

I replied then remembered we were in the wrong forum so I deleted my reply.

Nothing actually appears wrong with your commands.

Is your master root image from a previous release? If so, make sure you're using Direct Install in Magisk to patch the new boot image, then reboot.

 

[Jeroen1000]

I replied then remembered we were in the wrong forum so I deleted my reply.

Nothing actually appears wrong with your commands.

Is your master root image from a previous release? If so, make sure you're using Direct Install in Magisk to patch the new boot image, then reboot.

I'll try not to make it a habit posting in the wrong place.

So I got my phone and updated it to the 12.0.0 (SQ1A.211205.008, Dec 2021) SW. At this point it was _not_ rooted. Then I downloaded the factory image for SQ1A.211205.008. I patched boot.img and flashed that. tl;dr Bascially what your tutorial explains in the initial root section.

The only thing different I do is instead of rebooting to recovery, I did

adb.exe reboot sideload

So when I boot the master boot image using

fastboot boot <drag and drop master root.img here>

I did select direct instal in magisk. Nothing odds happens*. I am not sure I understand Magisk is patching the correct boot.img though. I even booted to the inactive slot to check the upgrade ended up there. But it didnt.


* believe my phone did reboot twice. That might be unexpected behaviour?

 

[V0latyle]

I'll try not to make it a habit posting in the wrong place.

So I got my phone and updated it to the 12.0.0 (SQ1A.211205.008, Dec 2021. At this point it was _not_ rooted. Then I downloaded the factory image for SQ1A.211205.008. I patched boot.img and flashed that. tl;dr Bascially what your tutorial explains in the initial root section.

The only thing different I do is instead of rebooting to recovery, I did

adb.exe reboot sideload

So when I boot the master boot image using

fastboot boot <drag and drop master root.img here>

I did select direct install. Nothing odds happens. I am not sure I understand Magisk is patching the correct boot.img though. I even booted to the inactive slot to check the upgrade ended up there. But it didnt.

What happens when you boot to the inactive slot? Check the build number. I believe Magisk may be trying to patch the inactive slot. So, if one slot is "old" and the other slot is "new", just boot the "old" slot, which probably still has a patched boot image, and select Direct Install in Magisk.

Personally I just use the factory image method as it flashes both slots.

 

[Jeroen1000]

@V0latyle I booted to the inactive slot (see below) and it was on the very same version 12.0.0 (SQ1A.211205.008, Dec 2021). The full factory image comes with a Google warning I decided not to ignore "Note that it's typically easier and safer to sideload the full OTA image instead."

 

[V0latyle]

@V0latyle I booted to the inactive slot (see below) and it was on the very same version 12.0.0 (SQ1A.211205.008, Dec 2021). The full factory image comes with a Google warning I decided not to ignore "Note that it's typically easier and safer to sideload the full OTA image instead."

View attachment 5507739

I'm confused, are you trying to update to January?

Is either slot rooted?

The reason why OTA updates are generally "safer" is because they install to the inactive slot; if booting the inactive slot fails for whatever reason, the system will revert to the original slot.

More details here

Basically this is how it works:

• Pixel devices have A/B slots
• While system is running on slot A, it can download and install OTA update to Slot B, then command a reboot
• If boot is successful, Slot B is set as active; the next OTA will be installed to Slot A
• If boot is not successful, system reboots to Slot A (the non-updated slot) and the update can be attempted again.

The idea here is that the device has a degree of "self recovery" wherein it will revert to a usable state if the update fails for whatever reason. This works regardless of whether the bootloader is unlocked.

Flashing the factory image only works on an unlocked bootloader for two reasons:

• Partitions are flashed directly from PC
• Partition images cannot be verified for integrity and authenticity

ADB sideload basically works the same way as the seamless system update, just from recovery. The OTA image is checked against a known hash before it is flashed.

All that being said, it's pretty much moot for those of us with unlocked bootloaders, to a degree - if something goes wrong, it's most likely your own fault, and you have to fix it yourself - the device won't be able to fix it for you. For instance, if something goes wrong with the factory flash for whatever reason, you'll have to figure out why and ensure a subsequent flash is successful. Or, if you accidentally wipe data during the update, you're screwed - there is no way to recover user data once wiped. The OTA on the other hand never touches user data. The factory update in of itself doesn't either - the update process might, specifically the script included, as it incorporates the -w option by default to wipe data. So, if User Johnny Knucklehead skims over a few guides that aren't specific to his device, and decides to update by downloading the factory image and running the script without editing or learning the commands...then he'll have to start from scratch when things go wrong.

 

[Jeroen1000]

@V0latyle slot A is currently rooted. Hence, the phone is booting off slot A. Not sure about slot B. And yes, I am updating to January. A/B seems to work the same as it does on my OP7T judging from your excellent recap.

Anyway, I noticed some "suspicous" behaviour.

1. after the sideload procedure completes, I boot to bootloader and boot the master boot image.
2. The phone starts booting (displays the G with the progress bar animation below) and then...it reboots again as I get to see the warning screen (again) about having an unlocked boot loader.

Believe this would fall into the "If boot is not successful, system reboots to Slot A (the non-updated slot) and the update can be attempted again." catergory. So I am now assuming my Full OTA updates fail. As to why, I do not know.

 

[V0latyle]

@V0latyle slot A is currently rooted. Hence, the phone is booting off slot A. Not sure about slot B. And yes, I am updating to January. A/B seems to work the same as it does on my OP7T judging from your excellent recap.

It's pretty much an Android standard now, almost all contemporary devices do it.

Anyway, I noticed some "suspicous" behaviour.

1. after the sideload procedure completes, I boot to bootloader and boot the master boot image.
2. The phone starts booting (displays the G with the progress bar animation below) and then...it reboots again as I get to see the warning screen (again) about having an unlocked boot loader.

I think what's going on here is you're immediately trying to boot the patched image instead of letting the update boot by itself. This is why:

Believe this would fall into the "If boot is not successful, system reboots to Slot A (the non-updated slot) and the update can be attempted again." catergory. So I am now assuming my Full OTA updates fail. As to why, I do not know.

You actually just said why without realizing it.

After the OTA is installed and the device attempts to boot the updated slot, the system checks to make sure everything was updated correctly. What's happening here is you're interrupting that process, and forcing the older boot image to boot, so when the system attempts boot, it sees a mismatch between the January system update and the older patched boot image. It then decides the update was not successful, marks that slot as "unsuccessful boot", and reboots to Slot A.

So, here's what you have to do:

1. Sideload the OTA
2. Reboot to system, do NOT interrupt the process, allow system to boot without root
3. Allow update to complete (watch notifications, it'll say something about completing update)
4. When update is complete, reboot to bootloader
5. Boot patched image
6. Direct Install in Magisk.

Let me know how that works out; if that's the ticket, I need to update my OTA instructions.

Failing that, I would say just download the January factory image and update that way, and manually patch the January boot image in Magisk.

 

[Jeroen1000]

@V0latyle Yes that did the trick indeed. Thank you! Guess there is no way escaping a full boot to let the update finish.
Did this behaviour change in Android 12 perhaps (maybe you wrote the insturctions for Android 11)?

 

[V0latyle]

@V0latyle Yes that did the trick indeed. Thank you! Guess there is no way escaping a full boot to let the update finish.
Did this behaviour change in Android 12 perhaps (maybe you wrote the insturctions for Android 11)?

Nope, it's always been true of seamless system updates since at least Android 9. It must have slipped my mind when I was writing the guide. I'll update it soon.

 

[GrandAdmiral]

Yes, sometimes this occurs on rooted devices. Keep trying, or use a different method.

And to confirm, I'm still able to use a master boot image (original update to Android 12's not image) to live boot and then direct install?

 

[canibuz]

Might want to add the latest safety net fix 2.2.1 doesn't require riru anymore.

Releases · kdrag0n/safetynet-fix

Google SafetyNet attestation workarounds for Magisk - kdrag0n/safetynet-fix

github.com

 

[V0latyle]

Might want to add the latest safety net fix 2.2.1 doesn't require riru anymore.

Releases · kdrag0n/safetynet-fix

Google SafetyNet attestation workarounds for Magisk - kdrag0n/safetynet-fix

github.com

Riru doesn't work with Zygisk so it's pretty much moot at this point

I don't provide support for Magisk or its modules

 

[V0latyle]

This may be some welcome news to some of you:

Magisk Alpha now supports installing to the inactive slot on Pixel devices, which should simplify things for those of you who prefer to update via OTA.

This is Alpha software, use at your own risk! It will probably break some things! The last commit failed to build, but I am sure it'll be fixed soon.

Github download page

 

[CarinaPDX]

Nothing else should be required. I personally don't update via OTA; I use the factory image. It's normal for the OTA to fail on a rooted device, although sometimes retrying it will succeed.

Uninstalling Magisk should not be necessary. I just updated my 5 and wife's 5a without changing anything - just updated using factory image, flashed patched boot image, and done.

For those who are wondering, this is how I updated my wife's 5a (and my Pixel 5):

1. Download and extract the factory image
2. Extract boot.img from the factory update image
3. Copied boot.img to device, patched in Magisk, copied patched boot image back to update folder
4. Reboot device to bootloader
5. Apply update:

   fastboot update device-image-buildnumber.zip

6. Let device boot and finish update; reboot to bootloader
7. Boot patched image:

   fastboot boot magisk_patched-23016_xxxxx.img

8. Open Magisk, tap Install, Direct Install, then reboot.
9. Done.

You can potentially save a couple steps by using --skip-reboot when applying the update, then simply rebooting to bootloader and flashing the patched boot image.

As mentioned earlier, after flashing a factory image to get to 12 and installing Magisk all was well. But the OTA didn't complete the install for the January update, and even restoring images in Magisk didn't help. So now I need to update in another way. This recipe is clear but IIUC the data will be wiped (factory images have the -w switch in the shell script). Is it possible to do this but delete "-w" so as to not wipe my data? Or perhaps I should just flash the OTA? Thanks for the help.