Dear all: below are my outputs from console: # ls 8712u.ko ehci-hcd.ko rt3070sta.ko usbcore.ko a.out printf.out usb-storage.ko uvcvideo.ko # ./printf.out /bin/sh: ./printf.out: not found # why busybox say file not found since you can see the file exactly exist in the folder? appreciate your help, miloody