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.