iscsi: operation not supported

[robinsmidsrod]

You can set the initiator-iqn based on some kind of pattern in an iPXE script conditionally, based on availability of certain attributes, like hostname, uuid, asset tag or mac.

I do that in my iPXE native menu shown here: https://gist.github.com/2234639

You'll need an updated iPXE for the menu feature, it just landed yesterday. The isset feature has been around for a long time.