read_from_hdd assumes that mlb was installed on the first hard disk (0x80). This assumption breaks when mlb was chainloaded by another bootloader from another disk. BIOS assigns 0x80 to the first hdd according to boot order.
I am not familiar with real mode programming, it might be possible to enumerate all disks and compare MBR disk signature at 0x1B8 to find out which hdd.
read_from_hddassumes that mlb was installed on the first hard disk (0x80). This assumption breaks when mlb was chainloaded by another bootloader from another disk. BIOS assigns 0x80 to the first hdd according to boot order.I am not familiar with real mode programming, it might be possible to enumerate all disks and compare MBR disk signature at 0x1B8 to find out which hdd.