Ok, you are flashing from the recovery image.I enter the backup images manager and select the image for installation and press ok on the remote, after that it throws out a message
So it brings up the message to give you the option of reflashing the recovery slot (if you select Yes, then it will replace all the current images in flash (eMMC) and remove Multiboot).
If you select No, then it will give you the option of choosing which slot you wish to flash.