Hi, I just had to go through this issue, steps were the following:
- download .deb from https://archive.debian.org/debian-archive/debian/pool/non-free/f/firmware-nonfree/firmware-ralink_0.43_all.deb
- extract bins: dpkg-deb -xv firmware-ralink_0.43_all.deb ./tmp
- copy bins to firmware folder: sudo mv /tmp/lib/firmware/* /lib/firmware
- reboot