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1.6.4 Firmware for SL1 and SL1S SPEED  

Same Old Shane
Member Admin
1.6.4 Firmware for SL1 and SL1S SPEED


  • Added support for the medical printer
  • Bug fixes


This is the final release of firmware 1.6.4 focused primarily on fixing the bugs in the code. Compared to the previous release 1.6.3, there are 105 pull requests.

Added support for the medical printer

This release extends support for the upcoming Prusa MSLA printer, which will specialize in the medical segment. Due to some differences in the workflow, the developers have branched the code allowing for firmware adjustments without affecting the user experience while using the SL1S SPEED.

Bug fixes

Reading invalid files behaviour fixed

In the previous versions, an attempt to read an invalid file led to a deadlock, requiring a printer restart. The error handling was fixed.

Exposure time adjustment error

In the print settings, changing the exposure time led sometimes to erratic behavior due to rounding errors in communication on the dbus. This is now fixed.

Factory reset didn't include screen brightness

The screen brightness of the touch screen was stored in a different place than the rest of the configuration values and was not reset with a factory reset. This was rectified and now the factory reset is performed correctly.

Inconsistent logging from motion controller

Certain information/confirmation messages from the motion controller were incorrectly logged as warnings. Since the purpose of the log is to store faults and errors, those messages will not be logged anymore.

MC firmware update notification missing

The notification during the Motion Controller firmware update process was missing. Now this message is correctly displayed.

Tilt home succeeded with disconnected tilt

Users have reported that in certain situations tower homing failed after a hardware upgrade and complicated adjustments of tower sensitivity were necessary to correct it. Version 1.6.4 handles this correctly.

Downloading logs to disconnected USB drive

When trying to download system logs to USB without a USB flash drive connected an incorrect message “Printer is OK” was displayed. Now, the printer behaves correctly and informs the user about the missing USB storage.


Download location;

Firmware update instructions;


Shane (AKA FromPrusa)

Posted : 22/12/2021 8:56 pm