CH340 dropping bytes (and other issues)

[SiliconWizard]

What DavidAlfa mentions is that indeed some USB3 host controllers (PC side) are more finicky with non-fully-compliant USB2 devices, and many claimed USB2 devices are actually not fully compliant, so that's why you *may* occasionally have troubles with some (poorly designed) USB2 devices when connected to a USB3 port. USB2-only host controllers tend to be more forgiving. This is a "known" issue, not saying of course that's the case with the CH340, but it can be with those fake FT232R chips.

[aeg]

https://github.com/SHWotever/FakeCH340DriverFixer

Most of the counterfeit chips are showing as USB2.0-Ser! instead of USB2.0-Serial from the USB descriptor (used by this utility to determine if the chip is likely to be fake

The device manager port name is determined by the driver, so maybe in the case of counterfeit device the WCH driver detects fake and puts the ! mark. IDK, not seen this myself.

There was a report a few years back of bad CH340 cables with USB2.0-Ser! in the actual descriptor string: https://superuser.com/questions/1555674/driver-bug-in-ch340-usb-to-rs232-converter-chip