Rommon Recovery image on Cisco3750x

The Cisco Switch 3750x device is in ROMMON, there’s not much that you can do. however, a method to transfer another IOS using a direct console connection with a PC (the transfer is over your console cable itself). This is called  Xmodem. Now the rate of transfer depends on the baud rate that you set for your console connection. My baud set to 115200. You can set the baud rate in ROMMON using the set BAUD command. See below:

switch: set BAUD 115200

This MUST also match the terminal program setting as well. So (I’m  using TeraTerm) under Setup, Serial Port, set the baud rate to match whatever you set it as in ROMMON. Now we’re ready to transfer the file. The command is :

switch: copy xmodem: flash:c3750e-ipbasek9-mz.150-2.SE.bin

Once you press enter, you see the following:

Begin the Xmodem or Xmodem-1K transfer now…
C

At this point, you need to choose the file location from the terminal program. Go to File -Transfer - Xmodem - Send and choose the file that you wish the transfer. The transfer will start and  you will see a transfer window pop up like this: (it will take less than 40 Minutes)

Once completed, you should get a prompt back to your ROMMON:

Begin the Xmodem or Xmodem-1K transfer now…
C…………………………………………………………………….                                                                                                ……………………………………………………………………..                                                                                                 ……………………………………………………………………..                                                                                                ……………………………………………
File “xmodem:” successfully copied to “flash:c3750e-ipbasek9-mz.150-2.SE.bin”

Now from ROMMON, boot from flash using the following command:

switch: set BAUD 9600 (or unset BAUD)

switch: set boot c3750e-ipbasek9-mz.150-2.SE.bin
switch: boot flash:c3750e-ipbasek9-mz.150-2.SE.bin

This will try to boot the IOS specified and if the transfer was good.

Loading  “flash:c3750e-ipbasek9-mz.150-2.SE.bin”…@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

File “flash:c3750e-ipbasek9-mz.150-2.SE.bin” uncompressed and installed, entry point: 0×3000
executing…

All’s good again!! The switch runs a POST, once everything checks out, you’re back into the familiar territory!

        — System Configuration Dialog —

• Would you like to enter the initial configuration dialog? [yes/no]: no
• conf t      !! enter conf t
• boot system flash:IOS-IMAGE.bin      !! don’t forget to set the image
• wr mem       !! and save it so it will boot also when it gets powered off

***************************************************************************************


An IOS recovery very slow xmodem  (you can tune it up to 115kbps)… but nowadays with a USB flash drive…

Here you can see how it works:

NOTE: Not all USB flash drives are supported, hence my recommendation to get several ready.

• USB pen drive max. 16GB format as FAT16/32
• copy the .bin image onto the flash drive
• connect the flash drive to the switch
• switch: flash_init
• switch: dir usbflash0:       !!check if the switch can read from USB
• switch: copy usbflash0:IOS-IMAGE.bin flash: IOS-IMAGE .bin        !!copy the image from USB to flash
• switch:set BAUD 9600
• switch: set BOOT IOS-IMAGE.bin (if the old image exists on boot,  unset .bin)
• switch: boot flash: IOS-IMAGE .bin        !! with this command the switch boots up with the image immediately
• Would you like to enter the initial configuration dialog? [yes/no]: no
• conf t      !! enter conf t
• boot system flash:IOS-IMAGE.bin      !! don’t forget to set the image.
• wr mem       !! and save it so it will boot also when it gets powered off

If you forgot set BAUD to 115200 to 9600

switch#configure terminal

switch(config)#line con 0

switch(config-line)#speed 9600

switch(config-line)#end

switch#wr