ER25 - The motion controller failed to be updated

This error message refers to a problem with the motion controller when updating the firmware. It indicates that there was a communication problem while updating.

The Ultimaker 3 has an Olimex board (enabling connectivity etc) and a mainboard (containing the motion controller). During the firmware update, the motion controller is checked and updated as well. If this goes wrong, the ER25 error message appears.

To resolve the error, first try rebooting the printer and performing the firmware update again. Ensure not to turn off the printer while the firmware update is in progress.

If the error reappears, there may be a connection problem with the electronics. Check the troubleshooting steps below.

Olimex - mainboard communication

This communication issue could be caused by any of the three parts involved:

  • The Olimex
  • The flatwire (which runs between the two boards)
  • The mainboard

To check these components, you will need to access the electronics at the bottom of the printer.


Caution: Make sure the Ultimaker is turned off and the power cable is disconnected before you start this process.

Note: Always take ESD precautions when exposing the electronics at the bottom of the printer. Handling the electronics in an unsafe way can cause damage to the machine. Submit a support ticket or contact your local reseller if you do not have access to ESD precautions, such as an ESD bracelet.

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1. Place printer on its side 2. Remove bolts 3. Remove Olimex cover

Gently place the printer on its left side. Then, manually lift up the Z stage.


From the inside of the printer, use the hex screwdriver to remove the two bolts that secure the Olimex cover.


From the bottom of the printer, remove the cover from the Olimex board and place it aside.


Connector pins

You will now see the red Olimex board. This consists of two boards, press-fit together. If these two boards are not connected properly, this can cause the motion controller error. Look closely at the four rows of connector pins. They should look consistent. If the pins are less visible on one side, the connection could be poor. Press firmly on either side of the top board to restore the connection.

See the images below for clarification. Although this shows a loose Olimex board, you do not have to disconnect the cables or remove it from the printer.





If the connection of the two boards is ok or restored, next check the flatcable. This is the single gray wire that connects the Olimex board to the mainboard. 

The flatcable should be firmly inserted into the wide black connector at the top of the Olimex board (as seen with the printer on its left side), with the red stripe on the left.




Also inspect the cable for any signs of damage. It runs behind the Z motor. Ensure it is not pinched.

If this cable looks fine, insert the power cable again and turn on the printer. Attempt to update the firmware again. If it is successful this time, and no ER25 appears, the issue is resolved. Move on to reassembly. If you still receive an error, also check the mainboard.


The other side of the flatcable is connected to the mainboard. To inspect it, also remove this cover.

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1. Remove mainboard cover 2. Check flatcable 3. Reconnect if necessary

From the inside of the printer, use the hex screwdriver to remove the two bolts that secure the mainboard cover.


The gray flatcable should be connected to the pins behind the print head cable (not shown here).


If necessary, push the connector firmly in place, or remove and reconnect it.


Also inspect this side of the cable for any signs of damage. The flatcable runs over the mainboard. Ensure it has not gotten stuck on any pins or between the mainboard cover and the panel.


Place the covers back over the mainboard (if removed) and the Olimex board. Align the covers with the boards and the slots in the panels. Ensure that all wires fit under the covers, or are guided through the slots in the sides of the covers. No wires must get stuck between the cover and the panel.

From the inside of the printer, insert the two bolts for each cover. Use the hex screwdriver to secure them. Ensure the hex nuts are still placed in the cover and keep your finger on them when tightening the bolts.

With the covers back in place, you can carefully place the printer in its upright position again.

Need further support?

If you found any signs of damage to the Olimex, the flatcable, or the mainboard, the damaged component(s) must be replaced. Contact support or your local reseller to enquire about replacement parts and repair instructions.

Note: If the errors persist after taking the steps on this page, but no damage was observed, contact support or your local reseller. Ensure to include the error number and the log files of your printer.

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