Managed to edit the MMC by booting from USB, mounting the MMC. The R2S is now up and running, with the mainline armbian. However, the CPU still spins in the kernel and generates a lot of heat. Idle load average is 2.02.

The problem was in the dtb which comes with the Armbian image, added the fix, now it is working as expected. Attaching the fixed dtb file, just replace it with this one and enjoy! Rename the attached file to k3-am67a-beagley-ai.dtb and copy it to your /boot/dtb/ti/ path and reboot. k3-am67a-beagley-ai.dtb_armbian_fixed

I ran into some trouble. I managed to boot the USB and then used armbian-config to flash the image to internal eMMC. However the script copied the USB UUID instead of the MMC UUID so now the MMC won't boot. I need to edit the MMC and change the UUID.

Thanks for the script @sven-ola. I got the R2S booted from USB. I had to tweak a few minor things. Where did you get the Ubuntu boot.cmd? usb start setenv devtype usb setenv devnum 0:1 setenv prefix boot/ setenv fdtfile dtb-6.6.99-legacy-spacemit/spacemit/x1_orangepi-r2s.dtb #setenv fdtfile spacemit/k1-orangepi-rv2.dtb setenv bootargs "console=ttyS0,115200 root=/dev/sda1" ls ${devtype} ${devnum} ${prefix} load ${devtype} ${devnum} ${ramdisk_addr_r} ${prefix}uInitrd load ${devtype} ${devnum} ${kernel_addr_r} ${prefix}Image load ${devtype} ${devnum} ${fdt_addr_r} ${prefix}/${fdtfile} booti ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr_r}

Wrote a script to change an Armbian desktop system for Spacemit GPU drivers and Chromium (attached). Tested with the two pre-installed Gnome images on my site (see https://privat-in.de/ goto Downloads). Some testing results: Spacemit offers Ubuntu noble and Debian trixie *.deb from their Bianbu site http://archive.spacemit.com/ For us, main diff here is Noble=chromium (Spacemit customized version) and Trixie=chromium-browser-stable (older and not customized). We need Wayland for the GPU, X11 does not work. With lightdm, each Wayland login freezes. Thus use gdm3. With gdm3, Xfce4 exits immediately, Kde-plasma shows drawing errors, Cinnamon works to some extend, e.g has video placing and window sizing problems. So the only useable GUI is Gnome. With Chromium under Gnome we can watch Youtube with 1080p (video / audio sync should stablize after some seconds). When doing this, CPU temperature is up to 75°C from the ususal 65°C, power is 4 Watts from the ususal 3 Watts. Script should work on other Spacemit K1 boards as well. If you miss some package from Bianbu, write a wishlist or make an PR on https://codeberg.org/sven-ola/spacemit-mirror spacemit-gpu-addon.sh