Contrary to most public documentation (and our code having that hard coded)
the primary partition table does not have to start on the second LBA.
Add -l/-L to the create command to move the beginnings of the
primary and secondary partition tables ("PartitionEntryLBA" or
hdr_lba_table field in the GPT header in spec or code).
This allows one to have firmware in the early (or late) disk blocks
assuming the first two (or last) disk sectors are still available.
This gives a layout like:
| pmbr | pri hdr | ... <gap> ... | pri tbl | <1st usable LBA> .....
..... <last usable LBA> | sec tbl | ... <gap> ... | sec hdr |
MFC after: 2 months