Recovering a bricked UM3

Problem description:

After successfully finishing an over-night print job, I switched off the machine as usual. Some time later, I wanted to start another print job and switched the UM3 back on again. It happened that the machine won’t boot any more.

So, after switching on the machine, the Ulimaker text logo appears on the front panel but nothing else happened any further.

In fact. the machine was not dead but inoperable, as the standard menu to enter commands does not appear any more.

  • The UM3 was running with a pretty old firmware (maybe too old): Jun 29 2017
  • and in conjunction with the latest Cura release: Ultimaker Cura 3.5.1 (64 bit).

In fact, the only thing I changed in between was a new Cura version.


In order to understand the problem and come behind the scene, I did the following actions:

HDMI cable + HDMI-Display:

The UM3 has a standard Olimex board running on a linux operating system (open source), so after unscrewing the cover (right behind the network connector) on the backside of the machine, the HDMI cable connector becomes accessible.

Plugging the HDMI cable at one side to the UM3’s olimex board and on the other side to a monitor, allows to view the boot sequence messages of the operating system.
Output looks like the following:

How to solve the problem:

Assuming that the problem is related to a broken boot image or similar, the solution is to create a new bootable image on a micro sd card, boot the machine and later on update the firmware.

Required steps so far:

  • Create a bootable image on a mirco-SD card

    • download recovery.img from Ultimaker download area
    • download win32diskimager-1.0.0-install.exe to write the recovery.img to the SD-card (and at the same time make the SD-card bootable).

  • insert the bootable SD-card into the UM3 olimex SD-Card slot

    • note: there is a connector-cable right above the micro SD-Card slot which need to be unplugged to get access to the sd-card slot


  • boot the UM3

    • note: the HDMI cable has to be removed, all boot messages are redirected to the front panel.

    • wait until the dial-knob (which normally turns to blue) turns to green.


  • remove the micro SD-card and reboot as normal.

Once the reboot has finished, UM3 asks to do some calibration related to the lifting mechanism of the 2nd printhead.

  • Update the firmware as usual - recommended! As of writing this article, Firmware now is on: Apr 03 2018.

That’s basically it.

Lessions learned:

  • Don’t use an old firmware with a new Cura version, maybe?