Stuck on forbidden sign, verbose boot shows scrambled screen

Hi all,

I finally decided to take the plunge and try to install a Hackingtosh.
While most things went ok so far, I got to the part of the installation... it shows me a forbidden sign, when I try to boot verbose, half of the screen is scrambled (not sure if anyone can do anything with the picture I made?)

Thanks in advance!

Laptop which I am trying to install MacOS Sierra on is a Toshiba Portege r830...

Stuck on forbidden sign, verbose boot shows scrambled screen