25.6.3 Memory Bank Swapping
The two physical banks BANKA and BANKB are mapped in the NVM main address space and can be swapped. If STATUS.AFIRST contains '1', then BANKA is mapped to the NVM main address space Base Address, otherwise it is BANKB.
The start address of BANKA & BANKB depends on STATUS.AFIRST and on the size of the Flash. Refer to the Physical Memory Map for memory sizes and addresses for each device.