> xmodem -cy c5400-boot-mz.123-1a.bin
Do not start the sending program yet...
device does not contain a valid magic number
dir: cannot open device "bootflash:"

WARNING: All existing data in bootflash will be lost!
Invoke this application only for disaster recovery.
Do you wish to continue? y/n  [n]:  y
Ready to receive file c5400-boot-mz.123-1a.bin ...
Erasing flash at 0xb8000000