Sry my fault,missed the log somehow (writing on phone where i do not see post when i write)…overlay was correctly applied,so waiting for rootdevice has another rootcause. Afair 6.6-r4 was one of early branches i did for r4,not sure it was working so far. Maybe you can try removing the rootwait (or root completely) via uEnv.txt (make var blank) or better using initrd to see what is detected from mmc driver.
Initrd=filename.zst
You can find an aarch64 initrd (cpio.*) on my gdrive
6.8 succedded - it just booted - Debian Bookworm. Happy af.
I’ll build Bullseye as well and check if it boots. If it does I’ll create a thread for BPI-R4 with Debian images. It’d be cool as well if you’d add it to “en:bpi-r4:start [FW-WEB Wiki]”
Thanks Frank!
Maybe you can share the images you built for others as start mine are heavily modified 
Nice Repo @frank-w ! Are you planning to add vyos-1.4 / 1.5 support to your scripted image creations…? Or do you have some light what to mod in order to achieve this…?
Thanks in Advance !
No because i do not know this os. You need a way to get a minimal rootfs as chroot like debootstrap for debian/ubuntu…have no idea how to do this for your os