This tool is just a p0c I wrote while working on bootkits. It allows many things such as dumping sectors on a specific device, placing 16 bit payload at startup (it writes a specific code which will load and execute your payload, and relocates the original bootstrap code which you can load and execute after processing), display ascii art (or simple messages) before booting (a special payload is generated), save/restore the actual bootstrap + partition table, etc.
Payloads will be loaded and executed at 0000:0800, and overwritten code is at 0000:0600. To execute original bootstrap, just copy 0x200 bytes from 0000:0600 to 0000:7c00, or load the sector with the original backuped bootstrap at 0000:7c000. To find it, parse the code at sector 1.
While writing anything on a device, a dump is performed, and I strongly advise you to keep this dump on a separate device, just in case you overwrite your partition table / bootloader :].
Dump 4 sectors : MLB.exe -p 1 -l 0 4
Display "pwn.txt" ascii art message at boot : MLB.exe -p 1 -aaW ".\pwn.txt"
Run "print_boot2" code at boot : MLB.exe -p 0 -irW "print_boot2"
Run "keypwn" code on PhysicalDrive1 : MLB.exe -p 1 -irW "keypwn"
Wipe 30 sectors (starting at sector #2) of PhysicalDrive1 : MLB.exe -p 1 -wipe 30
Backup MBR + part. table of PhysicalDrive0 into "backup.bin" : MLB.exe -p 0 -b1 backup.bin
The keypwn.asm code purpose is to be written into a removable drive such as a USB key. While booting it, it allows you to place an ascii art message at the primary disk startup (works the same as the ascii art feature of the regular tool works). It should not overwrite anything but the MBR code (not the bootloader : it checks for null bytes code caves), but the original 1st sector is backuped into the USB key (sector #0xF) for rescue purpose. The second option allows you to restore the saved data to the disk.