It must be the kernel update then. I can continue to boot from the Trixie installation on the main chip. And then use my rescuemobian script to continue trying the upgrades on the Bookworm installation. Edit this to your installation, and then continue to try upgrades from this temporary environment.
Code:
#! /bin/bash
cd /home/d1/root
mount /dev/mmcblk1p1 /home/d1/boot
mount --bind /proc /home/d1/proc
mount --bind /sys /home/d1/sys
mount --bind /dev /home/d1/dev
mount --bind /run /home/d1/run
chroot /home/d1