Hi, I’ve tried it on three different PCs using USB 1.0, 2.0, 3.0, and USB-C. I’m starting to think it’s something with the device itself. But it works 
Charging is fine and there are no issues—except for the SIM issue.
It’s not my first phone—I’ve had the Xperia I, II, and now this V.
I’ve always flashed new phones, but I don’t remember ever having to reflash one. I never needed to. So maybe reflashing works a bit differently. I’m surprised that dmesg shows nothing…