First of all if you are not sure you have the latest firmware, update that.
You need a usb stick, format that to FAT32 and put the file on the empty stick. Make sure printer is turned off, put the stick behind the printer in the usb port (next to network port) and start the printer.
It should ask you if you want to update the firmare from the stick -> yes.
If that doesn't help you can try to do a Hard Disk Recovery from service menu.