Due to the huge initrd.img-6.16.7+deb14-amd64 size (168 MB, mainly
because of the Nvidia firmware) with a small /boot partition (512 MB),
I've regenerated it without the nonfree firmware. But the kernel
crashes with a "kernel NULL pointer dereference" in nouveau, and
this leaves the machine with a black screen.

I've attached the journalctl output for this boot.

After that, I've regenerated the initrd.img again with the nonfree
firmware, and there is no such issue.

(There's Debian bug 1022068 also about a kernel NULL pointer dereference
in nouveau, but that was in 2022. I don't know whether this is related.)