i downloaded a cso file and when i tried to use umdgen to convert it to iso it says "Error! Next available LBA position is 35 but LBA [\UMD_DATA.BIN] position is 33."
why do you want to convert it to iso? A cso is just a compressed iso, so is exactly the same but uses up less space on your memory card. They play exactly the same as iso's, ie from the ISO folder on your memory stick. That being said...if you still want to convert it back to iso, what program are you using? i find PSP ISO COMPRESSOR by danny_kay1710 to be the best for me. IbizaGTI
For me, some games either run slowly or dont run at all while they're in .cso format. also, thanks, it worked.