I have the Frsky utility. I have the SmartPort connected to TX pad. Its "finding device.." but not flashing.

How do you wire up FrSky receiver to flash? (not using radio) 
Can you flash with CP2102 or similar UART USB bridge?

I believe you can use an ftdi adapter, but you have to put a diode in between the tx and rx pins.
If I recall correctly I also had to go into the settings on my ftdi adapter and invert something- rs232 signals.
I tried this method a while back and didn’t have much luck.

I found it *much* easier to just use the jr bay pins on the back of my tx16s.

If you’ve got access to a tx with a jr bay, Oscar goes over the wiring in this article:
https://oscarliang.com/flash-frsky-rx-firmware/



If you don’t have access to a tx with a jr bay, let me know and I’ll try to find or remember the process to flash via ftdi.