Dangrain

Hey just checking in.
I haven't forgotten about this yet, I want to make sure everything is repeatable and possible to do on multiple versions of armbian before I write a guide and confuse a lot of people.
Noticing that mpv doesn't work, I tried to do what jock suggested to Harleyyyu and update to a newer kernel version.
So far... no luck. Seems like the problem boils down to having to write u-boot.bin to the eMCP before burning the actual OS onto it. 
I'll write again if anything goes.

@Dangrain Glad to see its working now. please do a guide on it, not only will it help other people it will also help you how to do it again in-case you forgot how to do it haha!
 

Success! Thank you so much @Harleyyyu! It now boots perfectly off the eMCP. If anyone wants it I can write a small guide on how to do this, just to make this easier and faster for folks in the future.

I'm currently trying to build my own kernel for armbian bookworm, using this Github Linux-rockchip: linuxtv-rkdevc-hevc-v2 (6.16-rc1) Goal is to try and make hantro work with native mainline V4L2-Request-API to achieve zero-copy decoding and bypass the legacy Rockchip MPP.

i just want to experiment the OS and the VPU it self at this point

@HarleyyyuAs I was typing that I tried another last-ditch kind of solution (because truly you shouldn't substitute device trees) and changed the armbianEnv.txt
 
I added 'overlays=led-conf7' to the end of the file and added 'irqpoll' to the extraargs. I'm going to try huddling them all into a single .img and try to flash it to the onboard disk, thanks for your help, and wish me good luck.