So your post got me intrigued with the Rock Pi. I ordered one from Ali Express, with 16GB eMMC storage. It's a speedy little guy, that's for sure! At least, compared to a Raspberry Pi.

I spent some time and ported my Waveshare Stepper Motor HAT INDI driver to work on the Rock Pi 4B. That was pretty straightforward.

So I got everything built and installed, and everything works! At least for a few captures of the ASI 1600MM Pro. And then it stops working until I reboot. :(

dmesg shows a bunch of errors about "Ring expansion failed". Are you getting anything like that in your dmesg?

Apparently that's been fixed in the kernel 4 years ago! The Rock Pi people are using an ancient 4.4 kernel.

I'm going to try pestering them and see if they will at least apply the fix to the 4.4 kernel, if they won't update to a newer kernel.

Otherwise I may have to build a kernel from source, with the patch applied. Not my first choice, however.

-- Kevin