The information as relayed to me:
We use a software package of our own design to connect to the MSP430F6638 BSL on newly built PCBs. When the hardware is connected to the PC, we detect the presence of the board in question and proceed to use the USB BSL to load our firmware. No problem for many years. If the board does not connect, it is usually caused by a hardware issue such as a shorted trace on the USB bus, unsoldered USB pin, etc.. We correct the physical problem and reconnect the board to the USB and everything is fine.
Recently we have been unable to connect to about 6% of the boards in question. An inspection of the board turns up no hardware issues. We will even unplug and replug the board into the USB to make sure it is not a communication or connection issue. In the end, we use the JTAG and reflash the USB BSL then reconnect the board to the PC and everything is fine.
We can connect to the BSL and download our firmware only after the USB BSL is reflashed.
Is there a hardware or software issue I should be looking for which can cause the BSL to not respond until it is re-flashed?