Clear all

[Sticky] 3.13.2-RC1 Firmware for MK3, MK3S, MK3S+ is out!  

Same Old Shane
Member Admin
3.13.2-RC1 Firmware for MK3, MK3S, MK3S+ is out!

Greetings all;

We are pleased to announce a new firmware release;


  • Power Panic improvements
  • Submitted by the Prusa community
    • En-/disable Fil. sensor
    • Added M118 G-code (Octoprint/Prusalink)
  • Improved M914 & M915control for stealth mode
  • User interface improvements
    • Jump to 200°C/50°C in Temperature menu
    • Language Update information shown in the first row
  • MMU improvements
    • Added a Tune menu for IDLER|SELECTOR CANNOT HOME
    • Bowden length register added
    • MMU USB product string updated
  • Other features
    • Simplified variant names
    • Code optimization
    • Bug fixes
  • Known issue
    • Fan check

This is the first release candidate of firmware 3.13.2 focused on Power Panic and several other improvements.

Power Panic improvements

The main focus of this release is to improve the Power Panic behavior especially after we introduced the new MMU3 firmware and the Error states reported on the LCD of the printer.

Multi-material prints tend to be very long, so any sort of power failure can put the quality of the print at stake.

Any function that needs user interaction will pause the printer and move the hotend away from the print itself. This prevents the hotend from “scorching” the print and creating blobs. It also creates space to investigate the reported issue or perform the requested action. Previously, the positions were saved to the RAM, but these were lost during a power failure or a reset of the printer. This means the printer would try to continue with the print BUT at the wrong height and wrong position. This caused mid-air extrusions, the creation of blobs, and caused missing extrusions.

This has now been solved - All RAM values are saved to EEPROM during a power panic which ensures a better power panic recovery during MMU prints.

Power Panic recovery tested for:

  • Paused print ✔️
  • MMU Error codes ✔️
  • After a crash ✔️
  • Filament runout ✔️
  • Filament change ✔️

Power panic works only with SD card prints!

En-/disable Fil. sensor

En-/disable Fil. sensor with gcodes M405/M406 submitted by @Commod0re

Add M118 gcode

The M118 gcode was submitted by @RoboMagus see here. The M118 G-code allows the sending of a message (Serial print) to hosts like OctoPrint and PrusaLink to trigger actions, etc. See the pull request for more information.

Improved G-code M914 & M915 control for stealth mode

In addition to enabling M914 and 915 by default, these codes have been expanded to allow for more flexible control of the current printing mode via G-code (such as enabling crash detection selectively during portions of a print).

By default, changes issued are temporary (lost on printer reset), but by supplying the ‘P’ parameter, the change can be saved to EEPROM and made persistent. Alternatively, supplying the R parameter will revert any current temporary changes in favor of the saved value. Finally, the menu has been updated to provide visual feedback when a temporary override is in place via G-code

Jump to 200°C/50°C in Temperature menu

We are introducing a new shortcut. With a single clockwise turn in the LCD Settings -> Temperature menu, the temperatures will jump to 200 °C (hotend) and 50 °C (heatbed). The part cooling fan will be set to 127 (or 50 %) when turning clockwise from 0.

If needed, you can revert to the original way by rotating the knob counter-clockwise first, then you can use it the same way as before.

Language Update information shown in the first row

A minor change was introduced to avoid overwriting the version number during a language update.


MMU2S users reported that even after careful checking of their hardware, some units just cannot home the Idler reliably. Even though in the MMU FW 3.0.0 there has always been an option to tweak the Idler’s homing sensitivity (StallGuard threshold), some users had trouble with it.

Therefore, in case the MMU reports any of the Idler and/or Selector cannot home errors, there is a new option on the LCD called “Tune” which enables setting of the threshold value in a user-friendly way. Please note that the allowed range of values has been limited to prevent users from accidentally setting extreme values.

Bowden length register added

With the MMU FW 3.0.1, it is possible to set custom PTFE tube length. This has been implemented at the request of our community members who pointed out that there are various configurations for the filament setup and there’s a need to set a longer PTFE tube length. We limited the length to 1000 mm since longer tubes might introduce additional issues - we strongly recommend keeping the tube shorter rather than at the maximum allowable length.

This new register can be used to tweak the fast loading and unloading distance in case of non-standard installations. The register is persistent in the MMU’s EEPROM.
Unlike the previous generation of FW 1.0.x, the register now reflects the actual real length of the tube, not including any additional distances to the pulley or drive gears.

MMU USB product string updated

Since the new FW generation supports both MMU2S and MMU3, the USB product string has been changed to “Original Prusa MMU unit 🐑”. Please note that on some operating systems, this string is irrelevant and completely hidden from the user.


Simplified variant names

In the source code, we shortened the variant names to the minimum needed, as all Original Prusa MK2.5/S and MK3/S/+

  • use 1.75mm filament
  • use E3d v6 style hotenends
  • All MK3/S/+ use the same controller board
  • Exceptions are
    • MK2.5/S may have a RAMbo10a or a RAMbo13a board which have different pinouts
    • 3rd party modification

Code optimization

We optimized the source code and freed up some space for future features.

Bug fixes

  • Fixed a false FINDA runout event at the start of an MMU print on MK3S printers #4332 (Kudos goes to @mmoraes80@sruggier and @Braddg for helping us narrow down the problem and verify the fix)
  • Fixed an issue with Preheat heating for longer than intended #4338 (Kudos to @linzwatt for reporting the issue and to @sarusani for fixing it)
  • Fixed an issue where some users could not run first layer calibration because the LCD was stuck rendering the same fullscreen message repeatedly (Kudos to @sarusani for helping us test and fix this)
  • Fixed an issue where a print could be started while the printer is still loading or unloading filament, triggering a firmware crash. #3564

Know issue

Fan check

Currently, fan checks are not working reliably when returning from a paused print due to a fan error. If the fan gets blocked again after pressing resume, the printer may not show Stop print anymore and user needs to reset the printer. Also the Calibration menu is shown in the Tune menu while the printer tries to Resume the print from fan check issue.

Shane (AKA FromPrusa)

Posted : 12/09/2023 10:32 am
Famed Member
RE: 3.13.2-RC1 Firmware for MK3, MK3S, MK3S+ is out!

With a single clockwise turn in the LCD Settings -> Temperature menu, the temperatures will jump to 200 °C (hotend) and 50 °C (heatbed).

OMG — Miracles happen! Simple QoL improvements like this don't seem to catch the attention of fw and PS devs, so I'm glad to see this one made it in.

Posted : 12/09/2023 10:59 am
Active Member
RE: 3.13.2-RC1 Firmware for MK3, MK3S, MK3S+ is out!

Just updated to 3.13.2-RC1 and I´m getting thermal error on the 3rd layer.

Anyone else having trouble with this?

Im reverting to 3.13.1 again to see if helps...

Posted : 15/10/2023 7:31 am
Active Member
RE: 3.13.2-RC1 Firmware for MK3, MK3S, MK3S+ is out!

Had to do go back to 3.11 to get it not howl like demon at the 3rd layer.

Can I set the temp alarm levels somewhere in 3.13?

Posted : 15/10/2023 8:34 am
Active Member
RE: 3.13.2-RC1 Firmware for MK3, MK3S, MK3S+ is out!

Ok, have to admit that the only problem with the new firmware was a case of serious RTFM on my side.

After updating to 3.13.2-RC1 again but doing a thermal calibration before printing, my printer works like a charm.

Printed the same project again and it worked great a lot of new features!

Posted : 19/10/2023 5:45 pm

im having an issue where the mk3s+ is saying i need to upgrade the mmu firmware but i am already at 3.0.1 all 3 of my machines are doing this 

Posted : 23/10/2023 1:17 am
RE: 3.13.2-RC1 Firmware for MK3, MK3S, MK3S+ is out!

Any word on this issue see the post above 



Posted : 24/10/2023 10:02 pm