Boot Failure due to Missing Boot Flag

The server fails to boot with either of the following errors:

"Invalid partition table"
"Operating System not found"

Boot Installed System works properly and rescue mode can chroot the installed system successfully. The output of the parted command on a SLES10 SP4 server shows the following:

# parted -s /dev/sda print
Disk geometry for /dev/sda: 0kB - 16GB
Disk label type: msdos
Number  Start   End     Size    Type      File system  Flags
1       32kB    1579MB  1579MB  primary   linux-swap   type=82
2       1579MB  16GB    15GB    primary   reiserfs     type=83

No disk has the boot flag set. The BIOS relies on a boot flag being set to successfully boot the operating system. Set the boot flag on the correct disk partition using fdisk or parted commands.

# parted -s DEVICE set NUMBER FLAG STATE, where DEVICE is the path to the device being changed, NUMBER is the partition number, FLAG is "boot", and STATE is "on".

To set the boot flag in the example above, do the following:

# parted -s /dev/sda set 2 boot on
# parted -s /dev/sda print
Disk geometry for /dev/sda: 0kB - 16GB
Disk label type: msdos
Number  Start   End     Size    Type      File system  Flags
1       32kB    1579MB  1579MB  primary   linux-swap   type=82
2       1579MB  16GB    15GB    primary   reiserfs     boot, type=83
                                                       ^^^^^

Reboot the server.