The nRF9161 modem must be programmed with a firmware that supports the AT commands functionality needed for recommended production testing. The version of the Production Test Image (PTI) firmware can change over time. The firmware must be updated to a complete modem firmware that is product-certified.
You can check the version of the preprogrammed modem firmware with the %SHORTSWVER AT command. For more information, see Short software identification %SHORTSWVER in nRF91x1 Cellular AT Commands Reference Guide. For available firmware releases, see nRF9161 Downloads.
For information on programming using a customized setup in production, see Updating the modem in nAN41 - nRF91 Series Production Programming and nrfjprog executable or DLL in nRF Command Line Tools.
To update the modem firmware, connect nRF9161's Serial Wire Debug (SWD) interface to a debugger. Commercially available programming units, such as SEGGER J-Link, can be used.