3.12.0-RC2 Firmware for MK3, MK3S, MK3S+ is out!
Greetings all;
We figured we would start the new year off right with the latest version of the firmware for our Prusa Original MK3 series of printers (MK3, MK3s, and MK3s+). Please read the updates and instructions below.
Summary
- Thermal model protection updated
- Nozzle change menu
- XYZ calibration updates
- Bug fixes
This is the second release candidate of the upcoming firmware 3.12.0.
Thermal model protection updated
The thermal was first introduced in 3.12-beta1 and updated 3.12-RC1. This release brings further improvements and tweaks.
Protection is always active
The thermal model protection increases the overall security of the heating system and starting firmware 3.12.0, will be turned on by default. Since every printer is slightly different it is necessary to calibrate the printer first.
Modded printers
In case your printer is equipped with third-party components (heating or cooling), the thermal model might not be working properly. The developers are trying to expand support, but a large amount of data is needed to calibrate the model properly. Internally we have tested and analyzed over 150 000 OEM heaters and thermistors.
We are aware that third-party nozzle E3D REVO is not working correctly and we have an active GitHub issue where users reported their values. At this moment we don’t have enough data to analyze these, so please if you are a REVO user share your log files there.
Turning the thermal model protection off is not recommended, however, at your own risk it can be disabled via the serial line by sending G-code M310 S0 followed by M500 to make it permanent.
Calibrate the temp model on your printer
In case the printer is updated from any firmware prior to 3.12.0, or a factory reset is performed, the thermal calibration is considered invalid and must be executed again! If this process is skipped by the user, the printer will beep and possibly pause more often.
Temp model calibration is available in the LCD menu Calibration -> Temp model cal. as well in the initial setup Wizard.
- The calibration takes approximately 12 minutes and for the duration, you can’t give the printer any other commands.
- During the calibration the LCD status line shows which step it is going through at the moment.
- As soon as you see ”Original Prusa MK3S” on LCD, it is finished.
Please re-run the temp model calibration to ensure the best performance and minimize the temp model warnings,
- when you change:
- the nozzle
- heater block
- the heater cartridge
- the hotend thermistor
- the print fan
- fan shroud
- complete hotend assembly
- When you add a silicone sock
- When you move the printer to a different environment (enclosure, etc.).
Printer behavior
While preheating:
In case the algorithm detects any issue, the printer starts beeping. If the problem persists for about 10 seconds, the heating is stopped and the message “Thermal anomaly” is displayed. The printer continues beeping (calls for user attention).
While printing:
Similar to preheating, a discrepancy between the model and thermistor readings causes the printer to first beep and display “Thermal anomaly” and after about 10 seconds, the print is paused. The nozzle is turned off and the printer continues beeping.
Please note, that once a “Thermal anomaly” is detected the printer “locks” itself to prevent any possible damage and it is necessary to perform certain actions. See more information below.
Added Clear TM error
To “unlock” the printer in case a “Thermal anomaly” is detected, there is a new option in the menu LCD menu -> Clear TM error to temporarily clear/acknowledge the issue. As this is only a “temporary” solution proper calibration is recommended. In case the temp model calibration doesn't solve this, please contact Prusa support or open a GitHub issue.
Feedback reporting
To give positive feedback, please use a ✔️ here below the release notes. In case of issues TM: warning or TM: error start a GitHub issue, which should contain at least the following information:
- Reproducible: Yes/No
- Printer: MK3/S/+ stock or modified
- Modifications: Example E3D Revo or Copper block or different Fan shroud (with a link)
- Specific print causes issues. Please attach the printed model
- Try to add a serial log of the print failing.
Nozzle change menu
We added the necessary Nozzle change menu option under Settings -> HW Setup which disables the temp model temporarily. Please read Changing or replacing the nozzle (MK2.5S/MK3S/MK3S+) before you start. Please also keep in mind that changing the nozzle will need the first layer adjusted, as you will never be able to tighten the nozzle at exactly the same height as the previous one. We made this change thanks to the feedback from our community testers (see #3719).
XYZ calibration updates
A message displayed on the screen has been updated from It will take up to 12 mins. to It will take up to 24 mins. as some users reported that their printer needed more time. We added some status information during the XYZ calibration to give visual feedback that the printer is still busy.
Bug fixes
- Fixed
µmbeing shown incorrectly in languages other than English.
Please report any bug here:
github.com/prusa3d/Prusa-Firmware/issues
Download Link:
github.com/prusa3d/Prusa-Firmware/releases/tag/v3.12.0-RC2
How to flash the firmware:
help.prusa3d.com/en/article/firmware-updating-mk3s-mk3s-mk3_2227
Shane (AKA FromPrusa)
RE: 3.12.0-RC2 Firmware for MK3, MK3S, MK3S+ is out!
I installed the firmware, calibrated the printer including the new temp model cal.
fingers crossed I was hoping for a really positive result. There was an improvement but not what I expected. The printer kept beeping at me (thermal anomaly) even when using PETG but at least it didn’t cancel the print.
I decided since I had been working this printer practically every day since I installed it back in October 2022, that I would change ALL the hotend components for new. I know this was probably an overkill but I thought it would give the printer a bit of a spring clean and the best shot at what wanted to achieve. FYI - I installed a hardened nozzle.
My goal was to be able to print using PC Carbon Fibre, up to now this has not been possible since I would always get a MAXTEMP warning at the beginning or partway through the print which meant the print was stopped. At the time I did not understand enough about the printer.
Since October I installed the printer into the Prusa enclosure, with other options, which meant practically dis-assembling 1/2 the printer added MMU2S and now I have totally rebuilt the hotend ( not for the first time I might add) so my knowledge has increased considerably.Anyway I ran the full calibration again including the temp model cal and went in feet first.
I printed the brackets and cover for the electronics PCB on the MK3S+ and guess what it worked.
There were a few beeps, one pause, but at least I could continue and the print completed.
This is a HUGE step forward for me as I am checking all types of filament and temperature wise the PC-CF filament uses really high temperatures (285 degC) close to the the limits of the thermistor.
One or two suggestions I do have with temp modelling:1) A temperature setting could be added at the beginning, or set the initial temp to 280 or higher which would take into account higher temp filament and a wider temp drift envelope.
2) Include the bed temp in the modelling if not already done so as I did encounter a temp anomaly when running the PC-CF print. Normally the print would have stopped not knowing what the problem was but the print continued.
Bed temp 110 degC using PC-CFAll in all a great success for me, I also get beeps using PETG so I guess these anomalies are happening during lower temp prints but are not so catastrophic.
WELL DONE PRUSA👍
RE: 3.12.0-RC2 Firmware for MK3, MK3S, MK3S+ is out!
I have the same issue, can't calibrate the printer. Always getting error Thermal Runaway!!! "Great" firmware
RE: 3.12.0-RC2 Firmware for MK3, MK3S, MK3S+ is out!
Thermal Anomaly not runaway sorry