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@joepie91 there is a barely documented driver from Realtek for the RTL8821CU in the source tree (https://github.com/torvalds/linux/blob/master/drivers/net/wireless/realtek/rtw88/rtw8821cu.c). Would you be able to supply a device/model name or possibly an aliexpress link so i can get my hands on the hardware? Sadly, I wasn't able to find the device that corresponds to ID 0bda:b851 ;-;
Maybe I can try finding out what the issue is and hack a bit on the driver. It's entirely possible, that the driver just doesn't recognize the usb device ID, since they have a hardcoded list of device IDs and 0xb851 isn't contained (see attached screenshot).
I could also make a patch and send it to ya, if you're interested in testing the theory. Iterating would be easier with the actual hardware tho 
