Nvflash doesn't seem to work with Windows 7 64 bit. I see it is used as a bootable, will it work then?
Mazchazo, for me it works like a charm and I use Windows 7 64 bit: maybe you're looking to some guide which is a bit outdated.
You do not need to create any bootable media providing you are using the newer version of nvflash (I'm sure 188.8.131.52 is already enough, 5.105 is also newer, 5.118 is the newest) because it fully supports flashing in a 64-bit Windows environment.
A USB bootable media with nvflash and the original vBIOS come just handy if you have some problem after flashing and you don't have a second graphics (IGP o discrete).
So, providing you downloaded (for esample from TPU) the latest nvflash, you just need to run a cmd as administrator and, starting from the dir when you extracted it, run nvflash to extract the vBIOS (which will be extracted in the very same directory where nvflash actually is).
The entire process is a three step one: nvflash --save saved.rom
---> then make a copy with a different file name, for example edited.rom, and edit it (or let it mod by some other else): eventually write it back to the card ---> nvflash --protectoff
---> nvflash edited.rom
If anything should go wrong, just re-flash the original saved.rom
However, this is my strong warning: if you are unable to understand what to do, don't do anything.