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SDB Talk:Repair MBR after Windows install
I tested this procedure on Tumbleweed...
and ALMOST work... in Tumbleweed, once you has launched the "rescue mode", it will ask for login... log in in "root" (no password), but before anything, ask for the actual directory "pwd", and if you are not at "root" ("/"), use the command "cd .." or "cd /" to gain acces to the root directory. From that point, follow the procedure and it will work as stated. its assumed that /dev/sda3 is your linux directory, depending on how was the disk partitioned... if not sure, take a look with "fdisk -l" (minus L letter), to verify where is the linux partition. Once verified, go on with the following commands.
mount /dev/sda3 /mnt
mount --bind /dev /mnt/dev
mount --bind /proc /mnt/proc # maybe superfluous
mount --bind /sys /mnt/sys # maybe superfluous
If this preparation went well, perform the actual change:
if no error reported, then exit reboot
the base for this method, comes from https://en.opensuse.org/SDB:Repair_MBR_after_Windows_install