Only to place a link to this thread where the discussion is going on:
The part strictly speaking related to grub4dos is in this post:
Whilst the good Syslinux guys have decided (as seen since version 2.12) to pre-embed the size and the checksum (and write EFBEADDE as "filler"), the good grub4dos guys leave the whole set of bytes set to 00's.
The net effect is that IF the .iso is made with mkisofs AND the -boot-info-table option was chosen, Isobuster has no troubles with it.
Otherwise the size is still found as 2048 bytes since the bootinfotable in the first sector is all 00's.
Given the complexity of the options of mkisofs I would guess that the amount of GRLDR based .iso's around made with the "-boot-info-table" represent maybe 0.01% of the total number of GRLDR based .iso's.
And I plead guilty, too , for having built numberless of such .iso's without the switch:
I may ask tinybit/chenall (current grub4dos maintainers ) if they would consider to pre-populate the size and checksum in the bootinfotable in future versions of GRLDR (unless there is any size effect since GRLDR doubles as hard disk MBR + hidden sectors loaders).