IRSHELL NO UMD not working

i figured that people wouldve jumped on this before m33's no UMD trick if ever but i was wondering, when i go into usbhosts0 to play my homebrew, it says disc needs to be inserted. and i barely found out that my psp reading disc is messed up. I must of did something wrong when throwing on my full clear replacement case. Anyone know why? Along with the question if theres a way to not have a UMD in the drive to play my homebrew through irshell? It makes the sound like its trying to read the disc.