[Sticky] 4.3.1 Firmware for Original Prusa MINI/MINI+  

Same Old Shane


  • X-axis error during Wizard fixed
  • Safety timer not activated fixed


This is a bug fix release of the previous final version 4.3.0, where two bugs were discovered. There are no changes between firmware 4.3.1-RC1 released last week and this final release of firmware 4.3.1.

X-axis error during Wizard fixed

We have received a few user reports stating that in rare cases, the initial Wizard or XYZ calibration failed while performing the X-axis check. As a result, the print head with leveling sensor (M.I.N.D.A. / SuperPINDA) remained parked outside the heatbed perimeter and later, when performing Z-axis check, the leveling sensor was unable to trigger the heatbed.

This is now fixed. If the X-axis check fails, the user is informed and the test of the axes is canceled. In such a case please ensure that the print head can move freely along the entire X-axis length and make sure you are following the regular maintenance, see the Handbook for more information.

Safety timer not activated fixed

During internal testing, we have discovered that in some scenarios the Safety timer feature wasn't activated correctly and the printer kept the hotend temperature while waiting for the user to confirm a system dialogue. It is important to note, that the printer can still operate safely. This is now fixed and all scenarios were tested multiple times to ensure that the trigger of the Safety timer is correct.

Supported printer:

  • Original Prusa MINI

  • Original Prusa MINI+

Download Link:


How to flash the firmware on MINI:

  • Copy the firmware file (.bbf) onto the USB drive with FAT32 formatting
  • Insert the flash drive in the MINI's USB port
  • Turn the printer ON (or reboot it)
  • A new screen will appear
  • Confirm you want to flash the firmware

Please report any bug here:


As always, we wish you happy printing and look forward to your feedback!


This topic was modified 3 months ago 4 times by Jakub Dolezal
Shane (AKA FromPrusa)...
Posted : 15/02/2021 2:41 pm

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