RE: How do you flash the modem firmware on the NRF9151

Jonathon Ross — Wed, 09 Jul 2025 16:17:01 GMT

Okay perfect, I usually used the "erase and write" where as the .zip only allowed the "write" method, it seems. Thanks so much for the info, this got me to where I needed to be!

RE: How do you flash the modem firmware on the NRF9151

SwRa — Fri, 04 Jul 2025 13:03:06 GMT

Hi Jonathan,

[quote user=""]I don't imagine the modem core is programmed prior to shipping?[/quote]

nRF91 Series devices come with preprogrammed modem firmware, that must be updated in production to the modem firmware version the end product is certified with. The modem firmware is not included in your application build and must be updated separately.

[quote user=""]Would the Serial LTE Modem firmware still function without the modem core being updated and send any UART traffic?[/quote]

The Serial LTE Modem (SLM) application requires a working modem firmware.

You need to flash both the application firmware (your Zephyr-based app or a sample like Serial LTE Modem) and the modem firmware (modem core). These are separate binaries. You can either use the programmer app or nrfutil to do this. Using programmer, once you have selected the nRf91 device, Click "Add file" and select the modem firmware .zip file (do not unzip it). Then click "Write" to flash the modem. Then you can write the application firmware(Zephyr-built image (e.g., merged.hex or app_update.bin)).

All the above has also been explained here: Updating the DK firmware using Programmer and Updating the modem.

Best Regards,

Swathy