So I got atiflash working together with the polaris BIOS editor on linux. I managed to get all (I think so) the informations GOUZ would give a windows user... but then I'm not sure how to fiddle with that....
So I didn't read further as I'm using linux and don't have windows box
You should read that post , and learn...
if you managed atiflash and polaris bios editor working under linux (as you mentioned) , and you want to mod your bios , then you have to do exactly the same what windows users doing for bios mod ...
Just dont be lazy to read and learn ...

So try one more times: ( that tutorial is not just for windows users ):
TUTORIAL HEREYeah thanks, but I already saw this post and it starts with:
There are 2 ways the easy one and the proper one.
I will show you the easy way....
Undervolting will only work with Windows.
If you need undervolt bios for Linux you need to do the harder way
So I didn't read further as I'm using linux and don't have windows box
Your topic is : " how to mod a bios "
Are you talking about bios mod or undervolting your cards ? or undervolting your cards with bios mod or undervolting your cards with mining software under linux or undervolting your cards with tune software under linux ?