Cisco Download IOS Use XModem

Xmodem is procedure to download IOS to router or catalyst, why we need this procedure, whereas we can download IOS from tftp server to device with IOS command. why ? because IOS on Cisco router or catalyst is fail, IOS binnary in flash memory corrupt, flash memory on device is small to archieve many IOS image or may be we want to upgrade IOS.

Xmodem is console mode with cable console and rommon prompt. This method should be work on many router or catalyst series are 8xx, 17xx, 26xx, 36xx, 37xx, etc.

Here the step of procedure

o boot device to rommon prompt, if IOS failed usually come in it
o use application console with serial port like HyperTerminal, Zterm etc, for 8-N-1 at 9600 bps
o (optional) if device still can access IOS prompt use 'config-register 0x0' to boot come on to rommon
o type 'confreg' and follow the instructions, set console baud to 115200 change the boot characteristics to 'y' if want to change console baud (default 9600) and then reset
o change default console baud application console with 115200
o in rommon prompt type 'xmodem -c flash:IOS_NAME.bin'



o in application console do transfer and send with xmodem protocol specify IOS image location and then transfer



o 'confreg 0x2102' to set back boot option to normal IOS