After after much trial and error I have come to a point where I don't know how to proceed. My goal was to port the cfw from steward to the K3P. But now I'm not sure of it. Here are the things I tried:
I put stewards fw on a sdcard and booted it. Works as expected with the wrong screen settings etc. After that I check the possibility to run stewards fw from the external sdcard. flashing the internal card and opening the device is not so easy with the K3P. I checked the original firmware and it supports chroot! That means you can put any rootfs on the external sd-card and mount it as new root without changing the internal card!
I compiled my own rootfs with some changes with the configuration from steward and tried to port some emulators. I started with the git from steward and his changes to the emulators are very hard to track and a little, lets say destructive. They work for the RS97 and nowhere else. The problem with the tracking is, that he often commited patched code as initial commit. No way to know what changes he made but to find the original source and check that against the git repo.
I figured that the repos of dmitrysmagin are the source of some of the emulators steward and I used from the RZX-50.
I compiled the snes9x4d and ran it on the K3P. I was very disappointed. I had hoped for at least a small performance increase compared to default fw and the precompiled version of snes9x4d for the stock fw. There is none that I could see.
My next test was gngeo. I read in the RS97 thread that it runs neo-geo at 60fps on stewards fw. I compiled it for my test on the K3P and ran "Puzzle Bobble / Magic Drop". I got barely 45fps with drops to 30. Tested on the RS97 and its the same. No where near 60fps
I don't think that implementing the hardware IPU scaling will bring up the FPS either. As far as I know, scaling was only used to bring the original resolution of the emulated hardware to the resolution of the device, but even with the unscaled image of the snes, emulation is still to slow, so scaling isn't the main problem.
For OpenDingux: I tried the opendingux rootfs and used chroot on it. With this, you can run all the software from the the opendingux localpack. Problem is, that some of it seems to be optimized for the A320 IPU and you get a distorted screen and a lot of "unkown function" messages in the console. Disabling the scaling sometimes helps.
I think I'm with @lemmywinks
here: The device is cheap and not bad for what it does, but has severe limitations.
Right now I think it would be better to compile some software for the stockfw instead of doing it all over with a new fw.
I would love to see python and pygame on the device.
What are your thoughts?