Amd Radeons Overscan is reset after every boot

I have an AMD Radeon 6850 in my set up which is connected to my monitor via an hdmi cable. After installing the latest fglrx drivers, version 12.6, I need to drag the overscan slider all the way to the right to make the desktop properly fit my monitor. But now after every reboot the overscan image is very small and there is about a 2 inch large border around my display. When I open Catalyst Control Center the overscan slider is still as far to the right as possible, but when I slide it all the way to the left and then to the right again it fits my screen perfectly. How to I stop this small inconvenience?

Open a terminal with Ctrl+Alt+T and enter the following:

sudo amdconfig --set-pcs-val=MCIL,DigitalHDTVDefaultUnderscan,0

Then reboot.

I used @user188647 's answer as inspiration, but the command wasn't working.

So I edited /etc/ati/amdpcsdb, and in the AMDPCSROOT/SYSTEM/MCIL section, added:

DigitalHDTVDefaultUnderscan=V0

Then I shut down the X server, started it up again and voila! No underscan.

Inspired by: https://github.com/OpenELEC/OpenELEC.tv/issues/1636