Uninstalling the boot manager Boot-US
During the installation of the boot manager Boot-US the original MBR was saved
either on the boot disk 1 or on diskette.
In case the boot manager Boot-US had been installed on a primary partition
and the boot manager is removed, then the boot manager partition is deleted
and the former active partition is re-activated. The information about the previous active partition
is obtained from the saved MBR. If necessary, the first
partition is activated. The boot loader code of the MBR has not been changed
when the boot manager was installed and therefore does not need to be restored.
In case the boot manager Boot-US is installed in the MBR and the boot manager
is removed, the previous boot loader code must be restored on the MBR. This
code is copied from the saved MBR. Additionally the former active partition
is searched in the previously saved MBR and reactivated in the current MBR.
The menu command Boot manager / Remove... first checks the current
installation of the boot manager and then performs the appropriate type
of uninstallation. Normally it is not necessary to restore the complete track 0.
The commands bootusc bootmanager remove in the command-line version and Uninstall boot manager
in the boot manager perform exactly the same operations as the uninstallation from the GUI.
Detailed technical description of uninstallation:
By the above operations the MBR code is restored (only if necessary) and a potential boot manager partition is removed. Effectively the boot
manager is uninstalled and the previous state is restored.
- The current MBR of the boot disk 1 is read.
- When the boot manager is installed on the MBR the previously saved MBR is read from the second sector of the boot disk 1 (LBA=1),
and the MBR code of the current MBR is replaced by the MBR code of the previously saved MBR.
- When the boot manager is installed on a primary partition the previously saved MBR is read from the second sector of this boot manager partition or
from the second second sector of the track 0. The MBR code in the current MBR remains unchanged.
- The former active partition is searched in the previously saved MBR.
- A potentially existing boot manager partition is deleted.
- The former active partition in the current MBR is reactivated.
- The partition table of the current MBR remains unchanged otherwise.
- The modified current MBR is written back to the boot disk 1.
- All partitions on all disks are unhid.