I have ported retro-go to the Byteboi. For now, you can find it here: Release Retro-Go 1.43 for Byteboi · birefringence/retro-go · GitHub
I will try to have it integrated upstream.
Unfortunately, I can’t seem to fit all of retro-go into the 4MB flash. So you may want to build it yourself if you want to have a different selection of emulators.
Important: It will only work with the first revision of the hardware. Since I only have rev.1, I do not know if there is an easy way to distinguish rev.1 and rev.2. From the official CircuitMess firmware, I conclude that the second revision has a different display and the buttons are connected differently, so my port will not work on it at all!