Not a lot of people know about this, but it is possible to play Famicom Disk System games on a PSP. And it can be done with any old NesterJ version.

NesterJ

The version or fork of NesterJ does not seem to matter. For the test, I’ve tried NesterJ AoEX and NesterJ RX Mod - neither seems to work any better or worse when it comes to FDS support.

The main thing to remember is that you need a DISKSYS.ROM file (the FDS bios, 8 KB in size) at the root of the emulator’s folder. Otherwise when you try to load a .fds ROM, this will happen:

Once the DISKSYS.ROM is in place, simply choose the FDS game from the ROM selection menu.

A lot of FDS games required the user to change from side A to side B of the disk during loading. When the game prompts you to do so, just select DISK CHANGE from the settings menu, then CHANGE 1ST DISK SIDE B. The game will then resume loading.

There is a number of games (especially English-patched or ROM hacks) that simply won’t work on NesterJ though, no matter how you try to load them.

In those cases, do not contact the dev, as by now it has probably been at least a decade since they’ve last seen a PSP.

FDS support in RetroArch PSP

Instead, it can be a good idea to resort to the PSP version of RetroArch (yes, it has its uses).

Just make sure to have DISKSYS.ROM in the ms0:\PSP\RETROARCH\SYSTEM folder before trying to launch anything.

If you need to flip the disk during loading, press R to emulate ejection, then L to change sides, then R again.

The most recent version of the FCEUmm core should be able to handle even the trickier games.