My network has a limited number of USB ports. I need to boot a read-only instance of BT. I'd like to configure this to boot the ISO from the HD itself.

I'd be grateful for any grub stanza where someone got this, or anything similar, to work.

The primary OS is ubuntu, and in theory, grub supports the loopback mechanism, so I should be able to copy the ISO onto an EXT file system. A live ISO if you will, but not using a CDROM or a USB stick.

menuentry "Backtrack" {
loopback loop (hd0,2)/opt/bt4-r1.iso
linux (loop)/boot/vmlinux BOOT=casper boot=casper nopersistent textonly rw quiet
initrd (loop)/boot/initrd.gz

In practice, not so much.

EXT3-fs (hda2): error: couldn't mount because of unsupported optional features (240)

This was touched on in an earlier post, but the boot stanza the author was pursing required the 'find_iso/filename' capabilities, which appear not to be supported in the default version of grub. I am trying for anything that works...