Ubuntu AMD experimental driver watermark remover found thanks to : http://askubuntu.com/questions/206558/how-to-remove-the-amd-testing-use-only-watermark-from-ubuntu-12-10

amd-watermark-remover.sh

#!/bin/bash
DRIVER=/usr/lib/fglrx/xorg/modules/drivers/fglrx_drv.so
echo "Come on AMD!"
for token in $DRIVER; do
    echo "Removing AMD logo from "$token
    for x in $(objdump -d $DRIVER|awk '/call/&&/EnableLogo/{print "\\x"$2"\\x"$3"\\x"$4"\\x"$5"\\x"$6}'); do
        sed -i "s/$x/\x90\x90\x90\x90\x90/g" $DRIVER
    done
done
echo "Reboot computer to finish"