iPXE, iSCSI and int13

[NiKiZe]

build ipxe with make bin/ipxe.pxe DEBUG=int13:3
(rom-o-matic does not always do the correct thing, so local build box is always best for debugging)

most likely you will hit the "drive %02x does not contain a valid MBR" line here : https://git.ipxe.org/ipxe.git/blob/maste...13.c#l1778

You might also want to do a packet capture to check out that the blocks that iPXE receives actually contains what you expect them to contain.