After the product has passed all production tests, several settings can be applied to
limit the end-user’s access to the product settings and data.
Modem settings
When the production test is complete, the Nordic-proprietary %XPRODDONE AT command can be run. After the command runs, nRF9160 rejects the flashing of older firmware versions. AT command support for the RF test can also be disabled. For critical information, see Customer production done %XPRODDONE in nRF91 AT Commands Reference Guide.
Application settings
Enabling secure access port protection prevents the secure debugger from accessing the CPU and memories. This means that memory regions marked secure in the SPU and CPU while running secure code are inaccessible. Secure access port protection is enabled by writing the corresponding UICR register and issuing a system reset.