Code: Select all
// There is *no* requirement whatsoever for a valid floppy boot sector
// to have a 55AAh signature. UNIX boot floppies typically have no such
// signature. In general, it is impossible to tell a valid bootsector
// from an invalid one.
// NB: It is somewhat common for failed OS installs to have the
// 0x55AA signature and a valid partition table but zeros in the
// rest of the boot sector. We do a quick check by comparing the first
// and third word of boot sector; if identical, the boot sector is
// extremely unlikely to be valid.
The comparison of the first and third 16-bit word is done for all boot media, so it wouldn't help to simply try a virtual HD or DVD. But if you used TetrOS in a boot sector within a partitioned medium, success or failure would depend on the checks in the MBR code of the partitioned medium.
I've created #21861 for this.