The Ralink RT3090BC4 V20A is a vintage combo wireless adapter that provides both Wi-Fi and Bluetooth 2.1 connectivity. Because Ralink was acquired by MediaTek, official legacy drivers are now primarily hosted on MediaTek’s site or through manufacturer archives. Driver Download & Installation
The kernel still includes a staging driver for legacy Ralink chips. Ensure it’s not blacklisted: ralink rt3090bc4 v20a driver
Given Ralink's acquisition, there is no official Ralink support page. However, there are three reliable pathways: The Ralink RT3090BC4 V20A is a vintage combo
These OS versions have the best native support. Use the Staging Driver (Simplest) The kernel still
sudo apt update
sudo apt install firmware-ralink
sudo modprobe rt2800pci