If your bootloader is unlocked you can flash anything. This story is based around those using unmodified stock.
The bootloader cannot be downgraded, but you should be able to install an older version of Android.
Don't think so, but remains to be seen. We've already proven that an older version will run on the newer bootloader, by updating bootloader only - but we have as of yet not proven whether it's possible to flash older builds on the newer bootloader.
Sounds scary backwards. The bootloader is the last thing I want to update. With Samsung's you generally get boned upgrading the bootloader... forget doing a rollback, and enjoy the future shock. It's an interesting experiment nonetheless
It sounds to me like you were using an Android 12 boot image by mistake - somewhere between extracting the boot image from the factory 13 update, and patching it in Magisk, you were actually patching a left over Android 12 image. This is why I like using Pixel Flasher - it removes any existing boot image, patches a new one, and flashes it for you. Zero issues on my wife's P5a. I performed the factory update manually via command line on my P5. Either way, it sounds like you were probably using an old Android 12 boot image by mistake; it might have been left over in your phone's storage.I ran into some scary parts trying to upgrade. I was Magisk rooted.
Did my normal upgrade routine. Download factory image. Extract boot.img, put on phone, Patch with Magisk (25.2). Pull off phone.
Modify flash-all.bat to eliminate wipe and final reboot. Run it (no problems), then fastboot flash boot magisk_patched.img. Reboot.
Returns to bootloader, saying "Enter reason: boot failure". Oh sh... OK, fastboot flash the original boot.img. Now it gets the "your device is corrupt" screen. Doing another flash-all didn't fix it. Tried a lot of things before using a virgin factory image and letting it wipe. That didn't fix it. Everything I tried resulted in one of 3 things - bootloader w/"boot failure", "your device is corrupt" screen, or hung black screen w/"Google" (first stage boot? but never continues with the spinning balls, waited up to 20 minutes there) which needed a long power button press to get out of. Edit: it did end up on the "battery" screen a couple of times.
Finally got it booted on 13 using flash.android.com. Did a minimal setup, then fastboot flashed magisk_patched.img. "boot failure", so flash from web again. minimal setup, install magisk, do the patch thing starting with a fresh copy of boot.img, then flash it. This time it booted fine.
I'm not sure if the first boot.img I pulled got corrupted along the way, or ??? I also don't understand why flashing the original boot.img (which was done as part of both flash-all.bat and manually) didn't allow it to boot. Or why flash.android.com was able to fix it. I did notice that flash.android.com does a force flash (first time I've used it). What's the equivalent of flash.android.com's force flash? Just adding --force when using fastboot? I don't recall getting any errors which might have called for that.
tl;dr; I tried a rooted upgrade like I always do, it failed, needed to use flash.android.com to recover it.
Yeah, so it looks like it's just in the bootloader itself - if you attempt to flash an older bootloader, it'll just reject it.The rollback counter fuse is updated only on first successful boot of A13.
UPDATE: I sent my phone to google and they accepted my claim and gave me a Brand New Phone since it was still under warranty. I am so relieved that google actually considered the whole eFuse claim.
Thank you very much for the help and the links! I think I'll be able to get by with the translation, thanks again!You'll want to sideload the full OTA image once you have initially updated to Android 13 via OTA. Here's a good guide for sideloading an OTA for people who are not familiar with how to do it or have never done it before. You'll want to sideload the full OTA image. I hope you can translate the guide well.
It's an open forum, and everybody is entitled to their views and opinions, even if they're not authoritative truth.
@mike.sI do however understand the argument you're trying to make - that replacing the board shouldn't be necessary provided they reflash the updated bootloader, and I think you're right in that regard.
At the end of the day there's a lot of unknowns. We don't know exactly how Google fixed the brick, we don't know whether they opened the device, we don't know whether they reflashed the board or simply replaced it.
fastboot flash bootloader --slot=all <bootloader image>It's highly recommended you do this BEFORE updating, but if you didn't, do it as soon as possible.
I mean...I've kinda liked A12. But to each his own.
@blackhawk is entitled to his opinion, just as you are. Remember to keep your conduct civil and respectful:
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