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.

Permanent link to this article: https://tripplehelix.net/tftp-download-from-rommon/

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