Custom prusa firmware

[Makersmark98]

Hello guys, new to the whole github thing and learning as I go. I have a prusa mk3 which I have upgraded the hotend to a mosquito magnum, and increased the z axis to 600mm, but after trying for hours I am unable to change the firmware to allow the machine to print to this height. Would love a bit of help, can share the frame file to laser cut the extra height z if anyone is interested. marshall.suckling@utemaster.com. cheers