Firmware updating and flashing

Updated 3 months ago ​by Martin Lexa

Updating the firmware is recommended for all users as every new firmware version brings new features and bug fixes. To flash the firmware into your printer, you need a computer (running on Windows, macOS or Linux) and a USB cable, preferably the one, which was included with your Original Prusa i3 printer.

If you want to flash the firmware, the printer must be on.

Prusa i3 based FDM printers

  • To flash the firmware into your printer, connect the RAMBo board to your computer using the square-shaped USB-B 2.0 cable.
  • To flash the firmware into your MMU2S or MMU2 upgrade, connect the MMU control board using a MicroUSB cable to your computer.
Do not connect both USB cables at the same time! Each firmware must be flashed separately and only one logic board can be connected at a time.
- The file name with the firmware for the MK3S is: prusa3d_fw_MK3S_x_x_x_xxx where the x is the firmware version number.
- The file name with the firmware for the MMU2S is: prusa3d_fw_MMU2board_x_x_x_ where the x is the firmware version number.

  1. Both the firmware and the software to flash it (the PrusaSlicer) are available on our website. See the pictures of the printers and compare them with the printer you have on the table.
To check which firmware version you already have in your printer, power it up and in the LCD menu, go to Support. Scroll down and you will see the firmware version.
  1. Install the latest drivers.
  2. Open your PrusaSlicer, click on the Configuration menu and choose Flash printer firmware (even when flashing the MMU firmware)
  3. Click on the Browse button and choose the .hex file from the location where you have unzipped it.

As soon as the Status changes to Flashing succeeded! You can disconnect the USB cable

To upgrade the firmware, you can also follow our step-by-step guide: Upgrading the firmware
If you encounter any firmware updating or flashing problems, check our article about the most common errors: Firmware updating & flashing problems

Prusa SL1 printer

There are two ways to update the firmware of the SL1 printer.

  • OTA firmware update:

If your printer is connected to the internet, it can check whether a newer firmware is available online. Go to the LCD menu -> Settings -> Advanced Settings -> Update Firmware. Then you just need to follow the on-screen instructions.

  • USB firmware update

If the printer is not connected to the internet, you can update the firmware using a USB drive. Download the firmware file, place it on an USB drive and plug it into the printer. Go to the LCD menu -> Settings -> Advanced Settings -> Update Firmware. The system will recognize the file on the drive and initiate the update process automatically.


Find out more troubleshooting tips here: Community Forum | Assembly Manuals | Youtube channel |

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