I've managed to keep a working copy of the sx-key software up to Debian Stretch which I ran with wine version 1.8.7. I recently got a new T420 (well new to me) and have Debian Buster running on it. It's wine verson is 4.0.2. I can get the sx-key software v3.3.0 installed but I can't get it to recognize any com ports. I've stored the com1 and com2 with regedit and even created the links in the dosdevices directory (although I don't think you need to do that manually any more). Of course I've added myself to the dialout group as well. I just can't get /dev/ttyUSB0 mapped to com1. I don't think I'm missing anything and I know it did work in the past, so any tips would be super.