EK-TM4C1294XL: Target device failing to communicate with debugger

Part Number:EK-TM4C1294XL

Hello,

I'm using the TIVA Connected LaunchPad as a development platform for an EVM. We've used these extensively in the past. Recently, I've managed to cause a number of the target devices to fail while running the debugger in CCS and they cannot be recovered.

A few details that may provide some clarity:

1. I've replaced the target MCU on two of my LaunchPads with unopened devices from a previous EVM build. When the program reached main(), the debugger "lost connection with the target." After that point, I was never able to communicate with the target again.
2. In this failed state, the debugger MCU no longer enumerates in Device Manager. However, I've found that I can hold down the RESET switch on the target side, and Device Manager will update to show the Virtual Serial Port, the ICDI DFU device, and the ICDI JTAG/SWD interface. Upon releasing the RESET button, all three Stellaris devices disappear from Device Manager
3. MCU 3V3 still measures 3.28 V.
4. Target seems to draw about 17.1 mA without pressing RESET. Holding RESET reduces the current draw to about 5.6 mA.
5. JP1 = ICDI. JP2 and JP3 installed. JP4 and JP5 setup for UART.

Thanks and regards,