MSP430FR5969: Uploading New Firmware Over UART?

I think you can refer to this: http://www.ti.com/tool/mspbsl?jktype=recommendedresults

You need to use BSL to realize this function.

For the easiest way, you need to use ROM BSL, but you need 2 external PIN or you use command to jump into the ROM BSL.

For  another solution, you can use customized BSL saved in main memory.

Thanks for the reply. This is my first time dealing with this.

I have access to RST/NMI and TEST.

From what I briefly read in the MSP430 Flash Devices Bootloader (BSL) document, page 5, it looks like by applying the proper sequence, the program will start to execute at the BSL RESET vector. Is this correct?

From there, how would I write in my new firmware?