So, this is the continuation of the above saga.
With a brand *new* rpi4, I made two different 32GB SD cards of different makes from both:
Fedora-Minimal-34-1.2.aarch64.raw.xz
and
Fedora-Minimal-35-1.2.aarch64.raw.xz
I did not fiddle with partition sizes or anything like that, but I did connect an HDMI monitor and keyboard/mouse USB dongle. No network. 5V from a known good PSU. I simply cut the cards with:-
# xzcat Fedora-Minimal-35-1.2.aarch64.raw.xz | sudo dd status=progress bs=4M of=/dev/sdf and similar for the F34 file. With both boots, after many minutes, I got this repeatedly in the journal:
fedora kernel: mmc0: invalid bus width fedora kernel: mmc0: error -22 whilst initialising SD card
Nothing very definite appeared when I googled for some of the key words.
So, I have here two systems that both boot from an SD card, but then get confused about the SD card they have just booted from. Weird :(
Any insights appreciated, as usual. Thanks. :D