wanted to chime in and congratulate you on your awesome work. Your jailbreak made a way too expensive luxury toy a must have for any retro enthusiast. I've been playing on my new NT mini for some days now and have had a blast doing so.
Here is one possible small bug I stumbled upon. On the Game Gear core, Castle of Illusion has weird colors and won't normally. I tried both the US and Japanese rom from the Smokemonster romset which I believe are No Intro roms so should be fine. I am using your latest firmware.
On another note, I noticed that none of my famicom controllers intended for the expension port are working on my system. I tried several Hori gamepads and a XE-1 Pro Controller. No button input would be recognized. Is there something I need to enable in the menu to make them work? I had to make an RGB Scart cable following Analogues instructions from their webpage to have my system work with my CRT TV which requires a connection to its USB port. Could it be that this disables the expansion port somehow? Sorry if this is a stupid question, but I actually have no possibility to check myself as I don't own a HDTV.
And finally here is a suggestion for the file browser. Since a lot of file or folder names cannot be displayed fully as for the low resolution on a CRT, would it be possible to implement scrolling of the name of the highlighted file or folder, similar to what a SD2SNES card would do? It's sometimes impossible to know which file exactly you're choosing when two files names only differ by something the display won't show.
Sorry for the lenghty first post and again, thanks for your hard work. I'll be following this project as well as any news on your Z3K which sounds very intersting as well.