I wanted to make a arduboy with the SSD1309 2.42" screen but couldn’t think of a suitable form factor for it. I did notice that the screen was about the same size as the Gameboy Advance screen. I was going to put my homebrew arduboy in that but @bateske beat me too it, The next best thing was to use a Gameboy Advance SP instead.
It has a flash chip and I uploaded the FX game bundle onto it. It charges over USB C. I used the power switch to turn it on and off and also added a mute switch to the volume slider. I used the d-pad and A and B buttons and put the reset button where the brightness button was. The start, select, L and R buttons are not used.
I just wired the screen up with wires and snaked them through the hinge like the ribbon cable would normally do.
I put the arduino, DC DC boost and flash chip in on the board in the space were the game cart would normally go and then made a cover with a magnet in it to cover them up. This means you can still upload new games easily.
All the board files and the 3d print files are available on my blog post
Youtube video below