Wifi not supported on Pihcomm KE2P

Hello, I recently installed OpenWrt on a Phicomm KE2P and it works really well except the wifi driver (MediaTek MT7615D).
I read that it should work (but only 2.4Ghz or 5Ghz at a given time).

Is there somehing I've missed during installation?
(I've followed the instructions and flashed the image with uart and tftp)


Both data- and device page for this router explicitly mention this limitation, sadly without elaborating about the reasons behind it.

In my opinion WiFi doesn't work at in this router with OpenWrt v21.02.1.
Recently I uploaded OpenWrt currently I am looking for standard firmware to this device (unable to find it).

It seems that there is an issue with the driver to MT7615D (OpenWrt contains driver to MT7615E).