So maybe you can the firmware in this post?
http://www.geeetech.com/forum/viewtopic ... 20&t=17046
I'm not sure if it is the same as from Wiki,anyway you can have a try.
No Response from stepper motors mini g2s pro
Re: No Response from stepper motors mini g2s pro
Its a custom link on a popular stl file site, please contact the author there. Unsure of post rules concerning links to other sites, will pm you.