Recently we completed a relocation of 2 x 6500 switches. When powering on one of the 6500 switches, it booted into rommon. We discovered that the supervisor had failed. The supervisor was under maintenance and Cisco TAC sent a new SUP card. The switch loaded with the IOS that was shipped with the supervisor.
To transfer the original IOS and running configuration we setup a TFTP server and setup a temporary VLAN on the switch to transfer the files. The newer IOS was removed. The switch loaded with the correct IOS. The original running config was copied to startup configuration.
The switch was reloaded and we confirmed the configuration loaded fine. A maintenance was scheduled to connect the switch to the other 6500. There were no issues when connecting the switch back into the network.