It's not the brush machine, is it ... how is it formatted? If it's a formatted memory stick on a computer, then your PSP certainly doesn't know ... Open the PSP, and there is a formatted memory stick in the leftmost system (there must be an option to format the memory stick in the pile anyway). Xiao P's own formatting system formats the memory stick, which will automatically generate folders needed by ISO and other systems ... Like formatting, the ISO folder is not formatted, and it must be opened in the wrong way. ...