You shouldn't be setting MSP on UART1, just Serial RX, a port can only have 1 function, not 2, that is likely what is keeping it from saving.
That exposed length on the wires, on the RX especially, and probably the black on the FC too, are way too long, in the slightest crash they can bend and touch and short out.
I wish I knew a little more about the FC/ESC in those so I could be a little more certain, but there is almost no clear documentation out there on them.