So glad i hit upon this thread.
I had a similiar use case as that of OP's. Didn't find Rp3 performant enough, so i have odroid c2 running librelec. But now i want to run retroarch with kodi on another microSd on C2. I did similiar permuations with the images but just like as OP's they all failed.
If anyone got it working on c2, it would be greatly appreciated if they can contribute in updating the wiki or let know even if they were able to do so, so that investing time might be worthwhile. The "retropie-4-x-on-odroid-c2" link is helpfull but can't fully grasp if some steps are obsolete or still required.

@Phil333 did you pursue this further or dropped it for now?

thanks for this thread tough!

@mitu that was my first thought as well but the retropie user that's being used on my system is already part of those groups.

@strex I will add the gles flag in - but I think when I tested on the Odroid C2 I used an armhf userland image not aarch64. I suspect that is the most tested, and will work better for emulation, since only one emulator has aarch64 optimisations, whereas many have arm / neon optimisations which are not available in aarch64 mode.

A PC with a Core i CPU (and a Nvidia videocard) should be the best solution. The most arm boards are to slow for GameCube emulation.