For improved reliability and print quality, the Bear extruder is slightly taller than the original MK2.5S/MK3S extruder. We provide customized firmware to pass Selftest and (XY)Z Calibration for the taller size of the Bear extruder. Our firmware also provides a faster and safer rotation for hotend fan (if using something different than Noctua).

After the self test, you can go back to Prusa firmware if you prefer. However, you will have to use the stock hotend fan (Noctua).

Select and download the latest Bear calibration firmware here: github.com/bear-lab-3d/Prusa-Firmware/re...:

MK3S Einsy-Rambo 10a firmware name: Bear_Cal_FW***_MK3S-EINSy10a.hex

MK2.5S Mini-Rambo 13a firmware name: Bear_Cal_FW***_MK25S-RAMBo13a.zip

MK2.5S Mini-Rambo 10a firmware name: Bear_Cal_FW***_MK25S-RAMBo10a.zip

MK2.5S firmware comes as a ZIP file containing several languages of the firmware. They all contain English. Extract the ZIP file and choose the language you prefer to use (in addition to English).

If you don't know which Mini-Rambo board you have, please refer to this document