Raspberry Pi 4 8GB no more boots after doing dist-upgrade to Bullseye

Hi,

I installed https://raspi.debian.net/verified/20201112_raspi_4.img.xz on two Raspi 4 8GB and then dist-upgraded them to bullseye. Both no more boot, so this seems reproducible. There's just a blinking cursor on 1,1 after the Raspi's colorful square boot screen.

The first instance I only rebooted after installing tons of packages including a desktop and login manager, so it could have been anything.

So I checked a bit more what might have caused the issue when doing the second install. I know that upgrading the following packages alone do not cause the boot failure:

• linux-image-arm64
• raspi-firmware

Those were the most suspected ones, but are fine. I upgraded just them and immediately rebooted afterwards and it came up again. Then I dist-upgraded the remainder and it no more booted. Happened Thursday and Friday evening (3th and 4th of Dec. 2020).

I know this is not a direct issue with the images but likely a bug in some Debian package. I just don't know which. And since it's on a Raspi, I thought, this still might be the best place to discuss this before actually filing a bug report in the BTS.

I'll probably do some more tries (initramfs-tools, libc6, etc.) and see if I can pin-point this. But if someone else has an idea, I'd be happy to hear.

P.S.: Thanks for these images! Very much appreciated!