Quote Originally Posted by rodrigomartinho View Post
I made the test:
dd if=/dev/sdb bs=512 count=1 > /tmp/sdb_backup
dd if=/dev/zero of=/dev/sdb bs=439 count=1

And strange, all disks could be booted off, even when i explicitly told which disk to boot, using the f10 boot menu!
Aha! That shows that when you choose sdb the bios boots another drive instead.

Just double check the MBR is wiped by
dd if=/dev/sdb bs=512 count=1