Can something "break" if there's a mismatch between the SD and data?
Possibly. There is currently one major issue with the version of btrfs bundled with Bookworm: if you want (or might want) to move a btrfs filesystem between a 4B/400 and a Pi5/500 the Pi5 must not be running kernel8.img and not the default kernel_2712.img or you won't be able to mount the filesystem.
Same applies when going the other way. If you create a btrfs filesystem on a Pi5 running the default kernel you won't be able to mount it on a 4B/400. AFAIK it is not possible to run kernel_2712.img on a 4B/400.
Refer to the official documentation for how to specify which kernel to use.
Like, if I have a fresh installed Raspberry OS, would it be easy to get NextCloud and it's databank up and running again?
No Idea, sorry. I don't use NextCloud.
I strongly suggest you do some further reading and be certain you understand what you're doing and how to recover the system before you go too deep down the rabbit hole.
Statistics: Posted by thagrol — Sat Jan 25, 2025 9:18 pm