This error indicates that you have attempted to attach two SAN devices using the same drive number.

Things to try:

• If you are using multiple sanboot or sanhook commands, check that you are using the --drive option to give a unique drive number for each SAN device.

• If you have configured both a filename and a root-path via DHCP, note that iPXE will automatically attach the root-path as a SAN device (using the default drive number) before downloading and booting the filename.