4a doesn't have an operating system, and I can't re-flash.

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tails618

Member
May 22, 2018
21
0
Google Pixel 4a
I tried flashing the Android 12 OTA on my carrier unlocked Pixel 4a running Android 11 - it failed, and now my phone says "can't find valid operating system." Unfortunately, I can't flash android, because my bootloader is locked. And I can't unlock my bootloader, because I didn't enable OEM Unlocking in settings, which I definitely can't do now. Is there anything I can do to fix this, or do I have to use the Best Buy warranty I bought with my phone?

Edit: I forgot to mention that recovery and rescue modes are also giving the same error of not finding a valid os, and are thus unusable as far as I know.
 
Last edited:

JohnC

Senior Member
May 5, 2007
488
96
Google Pixel 4a
My thought is that bootloaders are locked to prevent loading "unknown" (third party) boot images.

But maybe the google images are digitally signed so they are "known" and can bypass the lock and be installed.

Because if "locked" truly means that even google can't update it, then that would mean it's impossible for any OTA update to modify the boot image (or kernel) for normal users (people who don't know about developer options).
 
Last edited:

tails618

Member
May 22, 2018
21
0
Google Pixel 4a
I had the same thought. Sadly, didn't work.

This is the output until I terminated it:

Code:
target reported max download size of 268435456 bytes
sending 'bootloader_b' (8357 KB)...
OKAY [  0.357s]
writing 'bootloader_b'...
FAILED (remote: Fastboot command (flash:) is not allowed when locked)
finished. total time: 0.513s
rebooting into bootloader...
OKAY [  0.070s]
finished. total time: 0.072s
< waiting for any device >
target reported max download size of 268435456 bytes
sending 'radio_b' (72372 KB)...
OKAY [  2.310s]
writing 'radio_b'...
FAILED (remote: Fastboot command (flash:) is not allowed when locked)
finished. total time: 2.401s
rebooting into bootloader...
OKAY [  0.070s]
finished. total time: 0.077s
 

JohnC

Senior Member
May 5, 2007
488
96
Google Pixel 4a
That's strange, because then how would any OTA update ever be able to modify a typical user's boot image/kernel because typical users don't or even know how to unlock their bootloader?
 

chris_xi

New member
Feb 20, 2017
3
1
Hi I think I found something!When I flash android 10 or 11its show this
1c28b8c7a97d3510ce31c94b1fefb6b.png

when I flash android 12 ,The bootliader is right s5-0.4-7018164 but show this
73235417f2152d022b316de61df4d53.png
 

shaitan667

Senior Member
  • Aug 28, 2008
    69
    6
    I tried flashing the Android 12 OTA on my carrier unlocked Pixel 4a running Android 11 - it failed, and now my phone says "can't find valid operating system." Unfortunately, I can't flash android, because my bootloader is locked. And I can't unlock my bootloader, because I didn't enable OEM Unlocking in settings, which I definitely can't do now. Is there anything I can do to fix this, or do I have to use the Best Buy warranty I bought with my phone?

    Edit: I forgot to mention that recovery and rescue modes are also giving the same error of not finding a valid os, and are thus unusable as far as I know.
    Try using the GrapheneOS web installer

    https://grapheneos.org/install/web

    I was able to unlock my bootloader using it even though I couldn't do OEM unlocking in Android
     

    a1291762

    Senior Member
    Nov 20, 2012
    638
    277
    yasmar.net
    My thought is that bootloaders are locked to prevent loading "unknown" (third party) boot images.

    But maybe the google images are digitally signed so they are "known" and can bypass the lock and be installed.

    My day job involves exactly this (but not android). Google absolutely signs the bootloader update, allowing it to be installed after or during the ota process.
     
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