GPT partitioned disks have a protective mbr in the first sector of the
disk, containing code to boot from the disk on non-EFI systems, along
with an entry for a single slice covering the entire disk. Some BIOSes,
e.g. Intel DQ965GF, will refuse to attempt to boot from a disk without
an active slice. A workaround is to mark the slice as active after
installing installing the pmbr, i.e.
gpt boot /dev/...
fdisk -a /dev/... (set slice 1 as active)
It would however be preferable for gpt to do this itself, either by
default, or by adding a suitable command line option.
Confirmed still a problem in 7.2-RELEASE-p2 with Intel D945GCLF2 and
Related problems include the PMBR starting at 0xffffff -- bin/115406
This is fixed in HEAD in r198097
Over to rnoland as MFC reminder
This is now in RELENG_7 and RELENG_8