I'm now using the same FW most others are (shared here), but FWIW I also had trouble getting my lens recognized on a MS Surface and I don't think it was cause of bad cables per se... I tried two different USB-C to C cables that I know are good and reliable, full featured high speed 5A e-marked cables that should be capable of handling anything, and neither one worked.
I was scrambling to get the lens updated for a trip after having run some tests with MF to ensure I'd be keeping it... On a whim I hooked up a USB-C hub and then to that I hooked up a cheap A to C cable I got for free (which I keep in my bag mostly for connecting up to rental cars that don't have wireless Android Auto), and voila, that did the trick.
It's possible the USB-C port on the lens is misbehaving when presented with a full featured full speed cable, or with the higher current (3A) sometimes associated with C to C, who knows... As a side note, I quite like the MF behavior and haptics on the 40/2, much nicer than my Samyang 45/1.8 but I even prefer it to my 35GM.
I don't use MF for much outside of lens tests so that isn't something that moves me, but still worth noting. The steps might be more coarse than on the GM but they're also more obvious, the SY just feels way worse to dial in. The SY looked somewhat sharper in the middle & wide open to me (comparable to the GM even), but otherwise the sharpness differences aren't anything to write home about IMO.
The SY also has a warmer color cast that's pretty obvious and would likely bother JPEG shooters.
