Refer to Ian Johnson's blog, it's pretty much the reference for this stuff:
http://solidoodletips.wordpress.com/201 … libration/
In short, you don't need to update firmware! In Repetier Host, go to "Config" --> "Firmware EEPROM Configuration" and edit the steps-per-mm value there.
The basic process is:
* Make sure when you ask the printer to feed 100mm of filament, it feeds 100mm of filament (by calibrating the steps-per-mm setting)
* Make sure when you ask the printer to create a wall 0.48mm thick it creates a wall that is actually 0.48mm thick (by adjusting the extrusion multiplier for that filament type - this value may vary between brands and colours of filaments).
SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi