If memory serves, you can only recover using an SD card. Sorry. 
Edit - If you've got an SD card in your machine, you could use the file manager/Midnight Commander/terminal to copy the recovery file from the USB stick onto the SD.
I'm pretty sure in the past i have used a USB Stick

It actually detects the recovery image!!
Oh well I'm home now!! will use my SD Card!!

Does anyone know what the "U-Disk" means
