RE: flashing modem firmware on thingy 91 x

a3p — Tue, 24 Feb 2026 11:31:01 GMT

that solved it, thank you!

RE: flashing modem firmware on thingy 91 x

Simon D-M — Tue, 24 Feb 2026 09:35:53 GMT

Hi,

I believe you are doing the right thing. However, if it shows as a nRF5340 it might be that the SWD switch is on nRF53 and not nRF91.

The SWD is connected to both Chips (nRF5340 and nRF9151) through a switch. This switch is not directly accessible. You have to remove the front cover to access it.

To remove the front cover (orange) you can open the Thingy91x by unclipping the two tabs (on the yellow back) that are retaining the front cover. Don't forget to open the port access door as we are removing the whole orange part. Then pull the orange front cover from the top (where the unclipped tabs are). Now you should have access to the switch and put it in the "nRF91" position.

Now you can close your device and retry to update the modem firmware through the JLink.

Let me know if that solved your problem.

Best regards,

Simon D-M