Ultimaker printer does not heat up when starting via SimplyPrint/OctoPrint

If you're having issues with your Ultimaker 1, 2 or 2+ not heating the bed or nozzle when printing through SimplyPrint or OctoPrint, keep reading to learn how to quickly fix this!

The core issue: "Ultimaker G-code flavor"

When printing normally, putting the file on a USB and starting through the printer screen, your printer will - based on its knowledge of your currently-loaded material - automatically handle heating up; this **isn't included in the print file **(".gcode" file).

But, when printing via SimplyPrint or OctoPrint, the Ultimaker printer does not automatically heat up unless it's specifically mentioned that it should do so in the print file, which by default, it isn't.

This is highlighted in this Ultimaker community post: https://community.ultimaker.com/topic/43246-octoprint/?do=findComment&comment=321060

So, in the end neither SimplyPrint nor OctoPrint changes your print file or directly causes your printer to not heat up: unfortunately, Ultimaker has opted for a different way of doing things on their earlier printer series, than the rest of the printing industry, and chosen to only automatically set the temperatures for USB-prints and not so-called "serial" prints (which is where a device like a Raspberry Pi feeds the print information to the printer, like via SimplyPrint and OctoPrint).

How to fix it: set the "G-code flavor" to "Marlin"

To fix this, you must go into Cura and click on the machine name, e.g. "Ultimaker 2+"

• Go to the "Machine" and press "Manage printers"
• In "Manage printers" make sure your Ultimaker printer is selected, and click "Machine Settings"
• In the "G-code flavor" option, select "Marlin"

You can see exactly how to do this in our interactive demo here:

And that's it!

Now your printer should heat up when printing via SimplyPrint or OctoPrint.

Be aware: possible different printer behaviour

Note that printing via USB might act different now; you should choose whether you want to print smart via SimplyPrint or OctoPrint, or if you want to print via USB, as the print files will be designed for one or the other.

Some users have reported different behaviour in the Start G-code setting for the "Marlin" flavor; it might fix the temperature issues for you, but also bring different behaviour in terms of "priming" the nozzle and heating up.

Feel free to modify the "Start G-code" Machine Setting to your liking, but note that the Marlin Start G-code does not seem to actually include the temperature commands, and how it will act if you insert these yourself is unknown; proceed only if you're comfortable with writing G-code, and you know what you're doing.

Updated on: 06/12/2025