How to load ISO with PSP 5.50 Gen D-3?

do you have 2 8gb icrosd card into a dual slot converter? the microsd cards wont allow u to drag and drop a file so large into a folder on the card. you can only drop it on the root.i dont know why, u can read the reasons on the net somewhere. i tried this also with my nintendo ds acecard. i just know that you have to like trick it by either zipping the folder and then moving it onto the card and unzipping it, or moving it like inside another folder. its hard to explain, but it works. also you have to change the movie from iso to mp4, thats what video file the psp reads. you also should use umdgen to compress the iso into a .cso. you just go up top and choose output then .cso. what else. you play the iso by putting it into the folder (everything sounds right that you did so far) and when u unhook ur usb, go to whatever the second to last choice is on the psp screen, like after pics and video but not wifi stuff, i guess its games or something ( i havent played mine for a while) and scroll down and there sould be a list of the ios's you put in the folder. also you have to press the select on to change the settings to m33 driver and the speed which should be 333 whatever and read mem stick instead of read iso. if you still dont get it email me and i'll go get my sons psp and try to help