Upgrade Rommon

I guess today is a rommon intensive day; I was curious what the process was to upgrade the rommon on a 2801. It’s pretty straight forward. Please note there is no real gain to upgrading your rommon unless there is a new feature that you need which is in the update.

1. Download rommon file for your platform. Example C2801_RM2.srec.124-13r.T5 is the latest and greatest for the 2801.
2. TFTP this file to Flash.
3. Router#upgrade rom-monitor file flash:C2801_RM2.srec.124-13r.T5
4. This will erase the Field-upgrade rommon memory area with the new file and reboot your router.
5. Confirm new rommon loaded with the show ver command output:

ROM: System Bootstrap, Version 12.4(13r)T5, RELEASE SOFTWARE (fc1)

That’s all there is to it.

TFTP Download from Rommon

I got tired of having to look this up all the time so I’m writing it up. So I had a 2801 I foolishly loaded an IOS image on that it didn’t have enough memory for and I got the dreaded reboot loop of death as it loads and crashes.

Solution is to use the break command to drop into Rommon mode and then load a new IOS image via TFTP either direct into DRAM or flash. Issue the following commands in Rommon mode it should assign the IP information to the first interface so on a 2801 FE0/0.

1. IP_ADDRESS=(IP Address)
2. IP_SUBNET_MASK=(Subnet Mask)
3. DEFAULT_GATEWAY=(Default Gateway IP)
4. TFTP_SERVER=(IP of TFTP Server)
5. TFTP_FILE=(File Name of the IOS image)
6. tftpdnld (or a –r to load right into DRAM)

Once booted you could then copy the image onto flash and of course change your boot parameters to match the new ios name and location.