Nice Job
He does say his GPCinema is in the firmware though, which probably means it doesn't support any other applications - you switch it on, and your in GPCinema. Hopefully, he'll patch (or create) a firmware that supports the SD card, and then release some source code to allow people to put it in there emu's etc.
I don't think the hardware itself would be too difficult - Smartmedia cards use an 8-bit bus that is connected directly to the processor, and SD cards use a 4-bit bus, so you can talk to them directly without any additional hardware. However, the firmware does require changes to talk to these cards, which is what Gomwing has done. Just need to hackup the original firmware, and then distribute some code so that existing emu's can be updated.
As some people may have known, I was trying to do a similar thing, but keep backwards compatibility (so 128mb for old apps, and ?Gb for new apps). However, I fried my gp32 in the process
And that after all the talk of "It`s impossible to surpass the 128mb limit".
It's still impossible. This is a completely new file system (and looks like new firmware), and therefore most likely not backwards compatible.
(If it is backwards compatible, then I'll bow down to Gomwings greater knowledge, and shut the hell up
)