I'm wondering: HP's idisk uses bytes at 0x1ba to print the legacy MBR's
"Signature". The UEFI Specification says the UniqueMBRSignature is located at
offset 0x1b8 of the MBR. But I found no documentation on these bytes in the
usual MBR docs. Furthermore I found some reference to "mystery bytes" at
offset 0xda of the MBR.

Is there any guru out there who can explain?