Ralink Rt3090bc4 V20a Driver -
If you have spent hours trying to make the work, consider replacing the Mini PCIe card. Compatible upgrades for the same slot:
lspci -nn | grep Ralink
sudo apt update sudo apt install firmware-ralink sudo modprobe rt2800pci ralink rt3090bc4 v20a driver
This is a PCIe 802.11b/g/n single-chip WiFi controller. Ralink (now MediaTek) released it years ago, so official driver support dried up after kernel 4.x. If you have spent hours trying to make