I have an SD card with Raspberry Pi OS, which is usually used for a Raspberry Pi 4B. I also have an old Pi Zero, and wanted to test something with it, but didn't have a spare SD card, so I turned my Pi 4 off and booted the Pi Zero with the 4's SD card. I didn't even need to login or anything, so I powered off in the middle of the boot sequence.
Now I've plugged it back in to the 4 and it's failing to boot. I had some peripherals/ethernet attached, so I stripped it down to just power and HDMI out, but still no joy.
It gets about as far as trying to start the Apache server (which fails as it has config that depends on an external hdd that I've disconnected), and checking for
apt upgrades. Then, it starts to repeatedly show the following message, about every 10 seconds (with different timestamps obviously):
[ 95.024390] rc.local: Oct 21 25:35:20.791 [FATAL] get-iface-ip: ioctl failure: No such device [ 95.035976] rc.local: ssh: no process found [ 95.038018] rc.local: scp: no process found
Is there anything I can do here to save the system without a fresh install?