When updating from the 1.0.6 to the 3.0.0 firmware version or above, go in LCD menu - Settings - MMU, and set it to ON.
Updating the firmware is recommended for all users as every new version brings new features and fixes. To flash the firmware onto your printer, you need:
- Computer running Windows, macOS, or Linux
- USB cable, preferably the original included with your printer
- PrusaSlicer and the printer's driver installed (download here)
To check which firmware version you already have on your printer, power it up and go to LCD menu -> Support. Scroll down and you will see the firmware version. The procedure for installing an older version of the firmware (downgrading) is exactly the same.
If you want to flash the firmware, the printer must be on.
Preparations
- PrusaSlicer and the printer's driver must be installed. If you do not have this installed, it is found in the Drivers and Apps package available on the same page where you download the latest firmware.
- Enter our our downloads section and download the firmware (green square). To find the correct firmware, see the name and picture of the printers/upgrades and compare it to your machine.
Flashing procedure MMU2S
- Connect the MMU control board using a MicroUSB cable to your computer. The printer must be ON!
- Unzip the .zip file to a folder on your computer.
- Open PrusaSlicer, click on the 'Configuration' menu, and select 'Flash printer firmware' (left picture), even when flashing the MMU firmware.
- Click on the Browse button (green arrow right picture) and choose the .hex file from the location where you have unzipped it.
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- The filename of the firmware for the MMU2S is 'prusa3d_fw_MMU2board_x_x_x_', where the x is the firmware version number. Do not select the MK3S firmware located in the same folder.
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- Make sure the Serial Port field displays the upgrade's name (purple square right picture) and has a COM port assigned (ex. COM8). Click Flash! and let the procedure complete.
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If the 'Serial port' field display anything but the name of the printer (ex. usbmodemfa141 or /dev/tty.usbmodem) you should try another USB port, reinstall the driver or restart your computer.
Problems when flashing
If you encounter any firmware updating or flashing problems, check our article about the most common errors: Firmware updating issues (MK2.5S/MK3S+/MMU2S/MMU3).
4 comments
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Michael
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Getting a MMU MCU Error prusa.io/04306 after updating my mmu2 to newest firmware.No issues before updating. What to do?Full error message:MMU MCU ERROR prusa.io/04306FI:0 FS:0 F? Temp 23
Philippe Lacoude
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I am getting a weird error. The flashing operation starts but it aborts with the following message: "Flashing failed: Error: The I/O operation has been aborted because of either a thread exit or an application request [system:995]"
The advanced log shows:
Flashing Original Prusa Multi Material 2 & 3 Upgrade (bootloader), looking for VID/PID 0x2c99/3 or 0x2c99/4 ...
Found VID/PID 0x2c99/4 at `COM4`, rebooting the device ...
Error: open: The I/O operation has been aborted because of either a thread exit or an application request [system:995]
The advanced log shows:
Flashing Original Prusa Multi Material 2 & 3 Upgrade (bootloader), looking for VID/PID 0x2c99/3 or 0x2c99/4 ...
Found VID/PID 0x2c99/4 at `COM4`, rebooting the device ...
Error: open: The I/O operation has been aborted because of either a thread exit or an application request [system:995]
daSpud
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Had the same problem. Removed the cable and reinserted. Tried again. It said COM4 and the device manager showed COM4. Then it switched to autodetected but it flashed this time. The advanced log showed dealings with COM4 and COM5. Don't know what 5 was doing in there, but it worked.
tcw82
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ok, trying to update the MMU2s, connected to MK3s+. USB cable is in the MMU2, printer is on. MMU2 is on. prusa slicer is started. Go to configuration -> flash firmware. window opens. select mmu firmware (just downloaded this from the site) serial port does not display "com XX". It shows: automatic detection (or something along those lines, my software is in dutch). flashing fails as right after the "Flash!" button is pushed, the text changes to red and tells me the MMU2s cant be found. tried the reset button, tried various other suggested steps... bought a new PC (old was windows 7, now on windows 11) but nothing helps. please advice (And perhaps update the procedure if the autodetect is acctually the norm now)
Giuliano - Official Prusa CS
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Hello. I advise to contact the tech support via email or live chat with a screenshot of the error message from the failed flashing attempt.
thekaj
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I'm having the exact issue with firmware 3.11.0 (1.0.6). When I load the firmware image, the serial port switches to "Autodetected", and then the flashing fails. Prior to loading the image, it says "Communications Port (COM1)". So my guess is that I'm having a connection issue between my computer and MMU2S, despite it working fine in updating my MK3S+. But having it switch to saying "Autodetected" when the firmware image is loaded makes it seem like everything is fine.
Giuliano - Official Prusa CS
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Hello. Check if other devices are connected to COM1. In case so, you can either disconnect the other devices or change COM port for the MMU2S.