My god, I couldn't believe it. I am running a Nextcloudpi instance on my Odroid HC4 and used the SanDisk Industrial SDHC 16 GB card (class 10, UHS-I) that was sent with it when I bought it some years ago. Reboots didn't work so I started searching around. I now cloned it to a 64GB SDXC UHS-I C10 V30 U3 A2 I had lying around and the reboots on Debian bookworm with Armbian 6.6.47 work like a charm now. Thank you, @deelan!
I decided to write this comment for better search engine coverage, since I searched around quite a bit and maybe not everyone is aware that the NCP images use Armbian. I hope this is okay, sorry for unearthing the thread.
