I think it is working now 🙂

1. copy /etc/config/wireless from current vocore2 firmware to same folder.
2. copy /lib/netifd/wireless/ralink.sh from current vocore2 firmware to same folder.
3. chmod +x /lib/netifd/wireless/ralink.sh

Then reboot, at least ap mode is working.
Still some parameters and sta mode are not working, but these bugs should be easy to fix 🙂

OK, next time I can make a patch and put to github.