How to get rid of GUID Partition Table

After switch between ESXi 5.5 CentOS 6.4 Xubuntu 13 and ESXi 5.1 plus Fedora 16 on my testing machine the other day and Anaconda has installed GPT on the hard drive.

It always tells me fdisk found GPT tables, I lost about 2 GB space.

Now, I want to fall back to MBR. Wildly used tool fdisk was showing a message Warning!! Unsupported GPT (GUID Partition Table) detected. Use GNU Parted. Frankly, I did not like it at all.

My first idea was to get rid of the first few sectors on the hard drive:

dd if=/dev/zero of=/dev/sda bs=512 count=1

Guess what, it did not work. After some time spend on the internet I found out GPT has a "backup" entry at the very end of the disc. I tried to copy zeroes over it, but it did not work too. The trick is quite easy, but it was more difficult to google this time:


parted /dev/sda
mklabel msdos
quit

Finally, the disc is back to traditional MBR. I think I don't like new things, sometimes.

Reference:
http://lukas.zapletalovi.com/2011/12/how-to-get-rid-of-guid-partition-table.html