1.fomat USB disk to "vfat". Note: You need to use Linux to format it to vfat.
2.copy initrd-recovery.gz, uImage-recovery and the latest RAIDiator to USB disk.Also copy the uboot.bin if you want to update the uboot.
3.plug in U-disk, press and hold the backup button while powering on the system. Don't need to hold the button after finishing coping kernel and initrd to RAM. wait untill the system finishes updating. then power will be off.