Hidden USB mode on Chinese GBA SP clone

I recently went to china and bought a few of these there it looks exactly like a original GBA SP except it has a USB port instead of a charger, it came pre loaded with 80 roms but you could load more as it wont detect in windows... ...But after some messing around with it I found it would connect if you insert usb and hit "R" three times, it has 1gig of space and works fine with other GBA roms. This isnt the version on Deal Extreme, and doesnt have a micro sd slot(like there version with usb) PS Sorry for the bad recording the rom I was copying was FFTA.GBA