linux n00b : no boot from external hdd

this linux n00b has managed to figure out how to use dd to make an exact copy of his ssd on an external usb hdd but he can't boot from it.
fdisk doesn't have an asterix for the disk.
does anyone know what he needs to do to make it bootable?

[edit]
when i try
[root@localhost user]# parted /dev/sdb1 toggle 1 boot
i get
Error: The flag 'boot' is not available for loop disk labels.

 

How about trying:

parted /dev/sdb set 1 boot on

Cheers.

 

same result with that instruction :|

 

"[root@localhost user]# parted /dev/sdb1 toggle 1 boot"
I think you want to make the disk bootable (sdb), not the partition on that disk (sdb1)
Try,
[root@localhost user]# parted /dev/sdb toggle 1 boot

 

These are wild guesses:

1. Try editing your /etc/fstab on the USB drive to mount sdb rather than sda.

Or:

2. Use live gparted on a usb drive to temporarily set the boot flag on the SSD drive to 0.


Also, your partition table will be wrong unless the external drive matches your internal drive exactly.