MSP432P4x1xT devices support 32KB of ROM, with the rest of the 1-MB region reserved (for future upgrades). The lower 2KB of the ROM is reserved for TI internal purposes and accesses to this space return an error response. The rest of the ROM is used for driver libraries.
The entire ROM region returns an error response for write accesses. The lower 2KB of the ROM always returns an error response for any access.