GTX 400 series aren't supported yet in this version, but apparently there's a demo going around for those who donate to the project.
NiBiTor (short for NVIDIA BIOS Editor) received its latest update. Version 5.5 of the program includes support for new GPUs and limited experimental support for new unknown GPUs. Apart from supporting new GPUs, the new version also includes its usual load of minor bug fixes that improve stability and usability.
GPUs supported from this version on, include:
* GeForce 210
* GeForce GT 220
* GeForce GT 230
* GeForce GT 240
* GeForce GTS 250M
A future version of NiBiTor will include official support for GF100-derived GPUs, though early-access to that version can be had by supporting the project.