SLAAEO4 November 2025 MSPM0G3507 , MSPM0L1306
In multiple bank devices, the bank swap is disabled by default. Multiple banks have the same property (Write, Read, and Execute) with different memory addresses.
Users enable the bank swap using the BOOTCFG5.FLASHBANKSWAPPOLICY field. Boot-code read this configuration and writes to the SYSCTL.SECCFG.FLBANKSWPPOLICY with the appropriate KEY (0xCA). With the hardware default, the swappable configuration is ENABLED, and the lower bank is used as a logical bank 0. While the default value of BOOTCFG5.FLASHBANKSWAPPOLICY field disables bank swap policy, so that the complete main flash region has Read, Write, Execute access property.
The bank swap behavior happens in the CSC stage, while the behavior goes into effect after the device issues INITDONE. Based on which bank (or pair) is executable, that bank (pair) receives reads and executes privileges and loses write and erase privileges. The other bank (or pair) is readable and writable, but not executable. This mechanism enforces the policy where after INITDOWN issued, the only save location for firmware updates is the writable bank, and can never be executed.
For more details on bank swap features, see the Flash Multi Bank Feature in MSPM0 Family application note.