Image 1/1: Install drivers

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Image 1/1: Unzip firmware
  • Go to and download latest firmware.

  • Unzip firmware

  • It's necessary to have firmware *.hex file on the same drive as FirmwareUpdater application! (For windows it's typically drive C)

  • You can easily recognise which electronics do you have by looking at filament diameter and LCD connection (both highlighted in picture)

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Image 1/1: Launch the FirmwareUpdater application
  • Connect your printer to the computer and turn it on

  • Launch the FirmwareUpdater application

  • Choose your firmware .*hex file

  • Choose serial port of your printer

  • If you don't see your printer on the left, hit this button and wait around 2 seconds

  • Hit Update! button

  • Monitor the status of updating

FirmwareUpdater? Can you please specify the exact file and relative path to it ? When I unzipped the firmware only c++ source files, headers and a make files were unzipped. There was no FirmwareUpdater.exe to run.

I was expecting to see the .exe in this folder but there is non.


Please advise

TimOdell - Reply

I found it under C:\Program Files\Prusa3D\Utilities.

pgiustino -

Hey GNU/Linux users:

Head on over to Update RAMBo mini firmware (OLD method) for how to upgrade. There will be instructions in the comments there, step by step.

PappaD - Reply

I don't see the printer. Only COM 4 - and I am not able to press Update.

Arno - Reply

hours and hours no upgrade

no lcd display

Joseph Mwadime - Reply

Just open Pronterface and try to connect to diferent COM ports first. If it connects, then its correct.

Vallo - Reply

This helped me! First open Pronterface i had to change the Baudrate to "115200" after that sucessful connection. Disconnect and try the update again, it worked

Hans Inauen -

I am not able to see the printer on any COM port even after hitting the Recan button. This is after installing the latest driver, Version 1.7.5. Is this an OS and COM issue or an issue with the Firmware updater v2. I also restarted my machine after installing the driver.

Jonathan Arteaga - Reply

Using Pronterface I was able to see that the printer was on COM 4 and could connect to the printer. I can now adjust the axes from Pronterface. However a firmware update did not work using COM4. After a Rescan I do not see the printer name in the drop-down list, just COM 4.

Jonathan Arteaga -

I disconnected from Pronterface. Relaunched firmware updater v2. Selected COM4 even though it was not recognized by name as the Prusa. Hit the Update button. No status indication aside from "update in progress" like Mark Jurisch noted in Step 4. After about 1 minute I got a successful update and confirmed firmware 3.0.9 on the Prusa LCD menu. This should be a bit easier to do. Thanks everyone for comments. I hope my comments help too.

Jonathan Arteaga -

Going to device manager worked for me - showed a mapping of printer to COM 3

Keith Mizen - Reply

Connected fine through COM3 via Pronterface. In firmware updater, upon choosing COM3 and selecting the .hex file (1_75mm_MK2-RAMBo13a-E3Dv6full.hex), I got the following error when I clicked update: "avrdude.exe: ser_open(): can't open device "\\.\COM3": Access is denied. avrdude.exe: ser_drain(): read error: The handle is invalid. avrdude.exe: ser_send(): write error: sorry no info avail avrdude.exe: stk500_send(): failed to send command to serial port avrdude.exe: ser_recv(): read error: The handle is invalid. avrdude.exe: stk500v2_ReceiveMessage(): timeout avrdude.exe: ser_send(): write error: sorry no info avail avrdude.exe: stk500_send(): failed to send command to serial port".

Based on Jonathan's advice, I closed Pronterface (which I'd forgotten I'd left open), stopped and restarted the Firmware Updater and the next attempt worked fine.

Greg Boyd - Reply

If you get a "node.js" error when using the "FirmwareUpdaterV2" included in the 1.7.5 package, try the "FirmwareUpdater" included in the 1.7.4 package. Worked for me. [Me: macOS Sierra 10.12.3 going to FW-3.0.10]

Tim Fou - Reply

Image 1/1:
  • Congratulations, now you have successfully updated firmware in your printer, HAPPY PRINTING!

The output doesn't give any indication of progress, or even if a connection was made on the COM port. Some indication of status beyond "update in progress, don't touch anything" would be nice, especially when it isn't working and sits on that screen until you exit the program without an error or indication it wasn't working.

Mark Jurisch - Reply

I agree, any hint as to how long this should take? Is it safe to exit if nothing seems to happen after x amount of time?

Maarten Knapen - Reply

Tried several times to download the zip file from the drivers page, no success despite different computers, mobile, etc etc no other network problems and Prusa support not offering any meaningful solution other than get someone else to download it, seriousy???

Foster Plender - Reply

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33 other people completed this guide.

Josef Prusa

Member since: 01/05/2015

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94 Guides authored


GNU/Linux Users, you can upload hex file using avrdude.

- Install arduino from your distro repos (Tested on Ubuntu 12.04)

- Download your new firmware for your board from:

- Extract

- Open a terminal and cd to extracted dir

- Upload by running (Change "3mm-RAMBo13a-PrusaNmk2.hex" to your board and extruder):

/usr/share/arduino/hardware/tools/avrdude -C/usr/share/arduino/hardware/tools/avrdude.conf -v -patmega2560 -cstk500v2 -P/dev/ttyACM0 -b115200 -D -Uflash:w:3mm-RAMBo13a-PrusaNmk2.hex:i

Alejandro Romero - Reply

Under Linux I flashed the firmware .hex file with avrdude:

avrdude -c stk500v2 -b 115200 -p Atmega2560 -v -P /dev/ttyACM0 -D -U 1_75mm_MK2-RAMBo13a-E3Dv6full-3.0.8.hex

Even better would be compiling the firmware myself, but so far the Arduino project didn't want to be built..

Jonas Jelten - Reply

I confirm it is working with avrdude on OSX too. Just uploaded doing: avrdude -c stk500v2 -b 115200 -p Atmega2560 -v -P /dev/tty.usbmodemFA131 -D -U 1_75mm_MK2-RAMBo13a-E3Dv6full.hex

To install avrdude: brew install avrdude --with-usb

Denis Pitzalis - Reply

You guys saved me here!....

With standard Arduino software install I was able to do:

$ pwd


$ ./avrdude -C ../etc/avrdude.conf -P /dev/tty.usbmodem1421 -b115200 -D -Uflash:w:/Applications/Prusa3d/prusa3d_mac_1_7_5/1_75mm_MK2-RAMBo13a-E3Dv6full.hex -v -patmega2560 -cstk500v2

and now my printer is back to normal...

Devon Heron - Reply

Anybody get continuous timeout messages doing this? This is from a Raspberry Pi running OctoPrint. I did hit the "disconnect" button in the OctoPrint web interface to try to prevent port conflicts.

pi@octopi:~ $ avrdude -c stk500v2 -b 115200 -p Atmega2560 -v -P /dev/ttyACM0 -D -U flash:w:1_75mm_MK2-RAMBo13a-E3Dv6full.hex:i

avrdude: Version 6.1, compiled on Jul 7 2015 at 10:29:47

Copyright (c) 2000-2005 Brian Dean,

Copyright (c) 2007-2014 Joerg Wunsch

System wide configuration file is "/etc/avrdude.conf"

User configuration file is "/home/pi/.avrduderc"

User configuration file does not exist or is not a regular file, skipping

Using Port : /dev/ttyACM0

Using Programmer : stk500v2

Overriding Baud Rate : 115200

avrdude: stk500v2_ReceiveMessage(): timeout

avrdude: stk500v2_ReceiveMessage(): timeout

avrdude: stk500v2_ReceiveMessage(): timeout

Henry Berg - Reply

I am getting this error:

Uncaught node.js Error

Error: EROFS, open '.fw.hex' at Error(native)

I am running Mac 10.12.3

I happen to have Node v4.6.2 installed

Richard Yee - Reply

Same error as @RichardYee, same Mac OS version 10.12.3, node version v5.10.0. What is the resolution?

Soumitra Kumar - Reply

I am also seeing the same Error: open 'fw.hex' message as mentioned above. On macOS 10.12.3, node v6.9.1.

Joe Fiorini - Reply

I tried the FirmwareUpdater on Win10 but the utility was unable to locate any com ports. I tried various thing spending almost a day until I found solution:

1) Remove the PRUSA 3D printer drivers in control panel, under printers & devices.

2) Remove all remaining PRUSA related software in control panel, under Programs and functions.

3) Turned off PRUSA i3 Mk2 and rebooted PC

4) Downloaded 1.7.6 windows drivers and installed them, using RMB and selecting Run as ADMINISTRATOR

5) Turned on PRUSA i3 Mk2

Now the Firmwareupdater found the COM ports and I could update firmware.

Per Hassel Sørensen - Reply

I had a problem with the FirmwareUpdater on macOS, so I just used avrdude as recommended in the comments. I did have to make one change though. After installing with brew install avrdude, the command I used was:

avrdude -c avrispmkII -b 115200 -p Atmega2560 -v -P /dev/tty.usbmodemXXXX -D -U 1_75mm_MK2-RAMBo13a-E3Dv6full.hex

You will need to look at what /dev/ device you should use. Try ls /dev/tty.usbmodem* to see it.

Andrew Willis - Reply

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