Set a Partition As Active on Linux

1. fdisk /dev/hda (Replace "/dev/hda" with the Linux name of the device where the partition is contained.)
2. Type "a" into the active "fdisk" prompt, then press "Enter." fdisk will prompt you for the number of the partition whose bootable flag you want to set; enter it, then press "Enter."
3. Type "w" and press "Enter." fdisk will save your modification to the partition table and exit. At that point, your partition will have been marked as active.