Ipod 6th gen classic wierd 120gb

My ipod 6th gen classic 120gb i flash modded it but i dont know because when i try too restore it i put 32gb in it my pc says "unrecognised file system" and then it says "format drive E: before you can use it" and it cancels the restore is there like a minimum amount of storage that the ipod can have if there is will a 64gb or 128gb sd card do the trick. Thanks,