MSP430F5437A: About BSL password

Hyungjae Cho

Part Number: MSP430F5437A

Hello,

This is about MSP430F5437A security.

I have more questions related to https://e2e.ti.com/support/microcontrollers/msp430/f/166/t/814820. There were answers about BSL password as follows:

- If JTAG is disabled, the only way to access the MCU memory is by providing the correct BSL password. If an incorrect BSL password is given, the FRAM memory is erased

Further questions are:

- After MCU fully erased by providing the wrong password, could the MCU be reprogrammed with new firmware and the new password?

- In the case the BSL password is leaked, the firmware in MCU could be readout and could be reprogrammed with the modified firmware, correct?

- Can BSL password be implemented as unique for each device/MCU?

Thanks, HJ

over 4 years ago

0 Mitch Ridgeway over 4 years ago

TI__Expert 6635 points

Hi Hyungjae,

I am looking into this a bit more on my end and will provide an update soon.

Thanks,

Mitch

0 Mitch Ridgeway over 4 years ago in reply to Mitch Ridgeway

TI__Expert 6635 points

Hi Hyungjae,

- After MCU fully erased by providing the wrong password, could the MCU be reprogrammed with new firmware and the new password?

Yes. The BSL password consists of the data located at the 16 interrupt vectors located at addresses 0xFFE0 to 0xFFFF. When the MSP is mass erased, the data in these vectors is also erased, which will give you a known password and will allow you to reprogram the device.

- In the case the BSL password is leaked, the firmware in MCU could be readout and could be reprogrammed with the modified firmware, correct?

Yes, that is correct.

- Can BSL password be implemented as unique for each device/MCU?

No. The BSL password is the data located at addresses 0xFFE0 to 0xFFFF. If all devices have the same firmware image, all devices will have the same BSL password.