On the Release Notes for v5.1 it's clearly stated that upgrading from 4 to 5 does not retain original configuration, especially IP address. However, there is a note about preserving it, following these steps: Step 1: Upgrade the other partition on the controller to 5.1 image as noted above, but DO NOT RELOAD Step 2: Backup the 4.x configuration file Step 3: Replace it with a new configuration file (in 5.x format, containing the desired IP information) Step 4: Reload Please correct me if I am wrong, but I guess steps should rather be: Step 1: Upgrade the other partition on the controller to 5.1 image as noted above, but DO NOT RELOAD. Step 2: DOWNLOAD (tftp, ftp) startup-config on a PC. This file is default Wing5.1's config, as said on the Release Notes:"On upgrade from 4.x to 5.x the 5.x controller will save the configuration from 4.x in another file on flash (so that ‘startup-config’ will point to the 5.x default startup-config)." Step 3: EDIT this file with the right IP data. Step 4: UPLOAD (tftp, ftp) edited startup-config on RFS. Step 5: Reload Please confirm. I need to upgrade remote RFS7000, and there is no way to use console interface. So this must work on the first (and unique) try.