Hi, my knowledge about Armbian is limited. For such a specific configuration/compilation I suggest that you open a new topic under "Allwinner sunxi". Best regards.

OK, good that you see the higher voltage selected. I have also seen it, but was on a NanoPi-R6C, although it did not work with RPi5 27W PSU, but OK with HP tablet 45W PSU. The rest is then a matter of kernel and DTB. My ROCK5B runs fine with rolling release/latest Linux kernels (Debian Sid, Opensuse Tumbleweed), currently 7.0.10 version. Don't know about NixOS (on aarch64), but maybe first get some basic stability with standard Armbian Trixie image (mainline based). It gets tricky when you mix vendor and mainline/distro based. Also vendor (6.1.115) can show various issues if you try/use various external HW. Like an mt9721u USB stick of mine causes a failure in paging on ROCK3A, so need reboot, then it works, but don't know for how long (weeks or months)

Yes, true. Meaning dirty spi Yes and no. If SPI is detected and valid it is used. However if this one detects a microsd card with a boot loader it will chain-load this one to ultimately load the os from microsd. Having mixups between vendor and mainline u-boot and/or mixed blobs (like ddr training) this will much likely cause issues.

I will try to download and flash the armbian u-boot to SPI. The main issue is that I don't have a fixed USB-C 12V power supply In the meantime I instrumented the fusb302 driver in my Nixos U-boot (v2025.11) an I can see the negociation working and selecting 20v 3.25A with my Lenovo laptop charger. But Linux still stop sudently, but that's a nixos issue, not an armbian on I guess.

The solution I've found is to use a HDMI to VGA converter and use the VGA port