I can add a bootable flag with the a command of fdisk.
How to do the reverse: remove the bootable flag of a partition?
I can add a bootable flag with the a command of fdisk.
How to do the reverse: remove the bootable flag of a partition?
If you are not comfortable with the command line may be gparted is better suited for you. Install it using
sudo apt-get install gparted
then open it
Once it is up and running - select the partition and then right click for "Manage Flags". After that you can select the flags accordingly.