@quaSimba: Fantastic work! Will put a link at the top of the tutorial for visibility.

Armbian recently merged and will be releasing (and backporting) a patched devicetree file for the Odroid C4 and HC4 that eliminates the second power-cycle "glitch" during boot. Hopefully this will fix at least one issue people have been reporting, where some HDDs (or other devices) do not react well to rapid power double-tap during boot. https://github.com/armbian/build/blob/main/patch/kernel/archive/meson64-6.19/board-odroid-sm1-regulators-boot-on.patch It will also be released (and likely backported) upstream in next Linux kernel release and/or fixes. Also, something else people have been reporting is the HC4 struggling to spin up two large HDDs at the same time. If you have an HDD with a "Power Up In Standby" (PUIS) setting, such as the Seagate IronWolf, then you can configure all non-system (non-boot) drives in this manner, and then mount and access them sequentially after the system has booted. Depending on how much power the HDDs use in regular operation, this might work to get both spun up and running. Theoretically, you could also access just one drive at a time and then place it back in standby before using the other drive. YMMV.

I have Dolamee D5 box. The legacy kernel 4.4.194-rk322x boots ok, but newer images from @jock or my own built image does not see EMMC. Any ideas? dmesgs attached. 4.4.194.txt 6.12.63.txt

@kil I also own a T95H and playing around with that now. Would it be possible getting your final dts, dtb and .config for u-boot? Thanks in advance & best regards

Hi, I could try to help, my board is exactly the same as yours. Can you provide me a source with instructions of how to do that?