The Bondtech LGX Shortcut Copperhead print head is a special unit that combines the LGX Large Gears eXtruder and the LGX Shortcut Copperhead hotend with a short filament path, which is suitable for all materials and especially with printing materials that are very soft and flexible. The LGX extruder can, of course, also be used with other hotends.

Bondtech has provided modded firmware for use with the Prusa i3 Mk3s. Not yet available for the Mk3.5s, however. This could change soon, as Prusa now allows the installation of custom firmware without voiding the warranty. More information here (click here).

Fortunately, you can still set up the LGX to work with the MK3.5 & MK3.5s:

First, we need to open the Experimental menu on the Prusa printer. How to do this is described here.

There, we set the Esteps to 800 and the maximum Z-height to 209mm.

I highly recommend performing an extruder Estep calibration according to this guide. According to this guide, I actually have 835 Esteps.

Now we need to set a PINDA offset with M851 Y12.00 . Currently, we can only set this in the slicer. This is what it should look like:

Unfortunately, you can’t currently set this permanently in the printer and save it to the EEPROM with M500. After a reboot, this is reset.