Perform the following command to backup the partition table:
sfdisk -d /dev/hdx > /part/to/pt_info.sfdisk
Partition Table restore
Perform the following command to restore the partition table:
sfdisk -d /dev/hdx < /part/to/pt_info.sfdisk
MBR backup
Perform the following command to backup the MBR:
dd if=/dev/hdx of=/path/to/image count=1 bs=512
MBR restore
Perform the following command to restore the MBR:
dd if=/path/to/image of=/dev/hdx count=1 bs=446
Notice that you need to include the option "count=1 bs=446", otherwise your partition table will be overwritten.
