U-Boot 2026.01-rc2 no HDMI-audio

[eselarm]

While doing various tests, also other bootloader than EDK2-UEFI v1.1 that I had in eMMC, I discovered that with 2026.01-rc2_armbian-2026.01-rc2-S365a-Pa203-He3cc-V062a-Bbf55-R448a kernel 6.18.0-rc7-edge-rockchip64 did not find/enable audio via HDMI.

I moved the computer to other room where I rely on the speakers in the monitor, else I would not have discovered it as I also use networked pulseaudio.

 

What works is 2025.01-armbian-2025.01-S6d41-Pdb4b-H2194-V062a-Bb703-R448a, so sort of last-known-good, got that via:

sudo apt install linux-u-boot-nanopi-r6c-current=25.8.1 and wrote the binary with dd to eMMC

 

Another issue is that the monitor does get out of sleep too late, so the loglevel=7 effect can only be seen on extra serial console, whereas with the UEFI bootloader, the HDMI gets always initalized properly, so before kernel is loaded.

 

Note that this is with booting via grub. So with EDK2-UEFI v1.1 bootloader, I get a normal Debian graphical kernel selection menu, like on x86-64. With Opensuse Tumbleweed it is slightly different, as that also automatically duplicates on serial console (if 't' is pressed , from 'text'). So this is actually quite ideal. The only disadvantage is that it does not want to store boot entries (but works on ROCK5B in SPI-flash).

 

I probably need an own build on SD-card first to see how 2026.01 (or later) can do the same as EDK2-UEFI v1.1 more or less.

 

I should note that with EDK2-UEFI v1.1 bootloader, I do not load the DTB that comes with the kernel version. I used the setting 'vendor' or 'mainline' in the UEFI settings, that gets stored well actually. Now with the 25.8.1 U-Boot, I manually added a devitree loader line in grub.cfg, but that will be overwritten, so need to see what makes sense.