I had the idea of swapping out one of the Harddisk from my Desktop box simply because it refused to boot under AHCI mode.
Under my plan, my desktop box would change from a combination of 640GB+1TB (where my debian installation sits) HDD to a 2TB+1TB. The 2TB had been sitting inside my portable HDD case for a long time. The portable case had minimal reliability to speak of because of it's tendency to lose connection after a while. I planned for the action for a lengthy period but never got to execute it as I didn't have the effort and the time required.
Here comes the mid-semester break (I don't think I have said that I am now a 1st year University Student) and that certainly means that I can afford to waste some time. So I opened the case and swapped the HDD. I brought everything back to place and powered the box on. It refused to boot. By then I realised Grub was actually on the 640GB that was replaced. By then I had no bootloader to go with. I needed to install Grub again on the 1TB HDD so that it boots and I get my OS back.
Without any second thought I went to search for my Debian Installation Disk. It turned out that I lost it and had to burn a new replacement. Easy job there. Here comes the hard part. When I tried to install grub back on to /dev/sda it showed an error of "This GPT partition label has no BIOS Boot Partition; embedding won’t be possible!". I panicked slightly and decided to google for an answer.
It ended up that I had to make a small partion on /dev/sda (1MB would do finely) and execute "sudo parted /dev/sda set <partition_number> bios_grub on" in a shell of any sort. Easily done and I hit the reboot button. When it finished doing POST, Grub came back on and once again I was a happy man.
Ended doing some cleanups and compiled 3.4.0-rc1 for my Debian box. I also made a 680GB btrfs partition to test the reliablity of this young filesystem.
