I know there are plenty of similar threads all over the Internet but unfortunately, mine is a combination of specific settings which made me open a new thread.
I have a ASUS U36SD laptop with preinstalled Windows 7. I shrinked its partition and managed to install a BackTrack (basically Ubuntu) on the free space. My partition configuration was like this and it was working:
[25 GB recovery] [150 GB Windows 7] [10 GB BackTrack] [530 GB Data]
I also had it booting with a Windows loader instead of Grub because I wanted a TrueCrypt systemdrive encryption and that does work only with a native Windows Loader.
So far everything was working and I was happy.
But yesterday, my linux ran out of space and I also noticed a new version has been released so I though I'd reinstall it. I shrinked the Windows partition 10 GB and deleted the Linux partition. I booted into live CD of new BackTrack and installed it on the free space. I selected NOT TO INSTALL GRUB on MBR, instead I installed it on the same partition as the Backtrack itself (not to overwrite my TrueCrypt MBR, which would make my data inaccessible). Then I used "dd if=/dev/sda3 of=/tmp/btsc.bin bs=512 count=1" to copy bootsector of that partition to a file, which I transferred to the Windows loader like it was before.
Now I have this setup:
[25 GB recovery] [140 GB Windows 7] [20 GB BackTrack] [530 GB Data]
But from that moment on, when I select to boot Backtrack from the Windows loader menu, I just get stuck with GRUB rescue mode and error message "unknown filesystem".
I have read that this error is caused by sudden partition changes which shift partition counting but between installing the GRUB and trying to boot is just a restart to Windows to import the copied bootsector which doesn't change the p. table at all..
Please help! :)