Looked at minimal linux distros.
Tried out libreelec first (SD card boot), had to play around a bit to find an older distro that would work with the hardware plus find a device tree file that would work. After trying some combinations I got it working, kinda, it wasn't too bad just basically kodi on a minimal linux os. Only problem was the ir remote didn't work anymore (I had to use USB mouse). After some reading it
seemed possible to setup ir remote to work, but
more messing around and I would need to ssh into the box and reboot on every try. As I said, possible, but at this point I thought maybe coreelec install might do better
So I setup coreelec SD card boot. Experience from my libreelec tests taught me what device tree was close to what I needed for the hardware. Took a few tries but I got it working.
IR remote that I had used for android (original and coolio install)
still didn't work, but that's ok as I had already read that coreelec supported some different remotes including Xbox 360 media remote
I've got a couple of the small white remotes so I used that and it's working fine.
Next was the final part of my experiment. Testing a few generic bluetooth USB dongles with a PS3 media remote (my intention was to see if it would work so no need to point at the box for ir remote to work).
First one I tried didn't work, second one I got the remote to pop up in the BT list (while holding start and enter) and then I just had to use the 360 remote with my other hand to select pairing and trust this connection.
So now I've resurrected a shitty old android box: quad core Amlogic 2GHz (x64) with Mali 450 GPU, 1GB ram, 8GB rom, RTL wi-fi and 100 lan port.
It can now run 1080p 60Hz x264/x265 vids
without stuttering (on android it was only 100% smooth with 720p), plus running from 32GB ultra SD card actually seems to make a difference (maybe that's just the minimal OS though, idk).
Also, I added bluetooth to it.
Oh yeah, forgot to mention the male to male USB cable I'm using; I'm sure I have at least one here somewhere but after looking for nearly an hour I gave up and made one. I was so dodgy about it I just cut up 2 cables, spliced the wires and didn't even solder. Just used electrical tape and checked continuity