M2 Wifi Card for Pi | DIY Mobile Router Project

Hi there,
i am currently building a mobile vpn capable router (basically a glinet mudi but a lot faster)
As base i am using a pi cm4 (running openwrt & wireguard client) and a modified netgear nighthawk m5 connected via rj45 (uplink). So far this is working great during testing i got nearly 740mbit down / 120mbit up over 5G with vpn connected measured from the pi.

The only thing left to figure out is how to get it to the client devices. The onboard wifi of the pi works but is painfully slow & i kinda want to avoid usb ones bc my current board only has 2.0 so i would need to get a different board.

2.4 & 5ghz
AP Mode
Work with openwrt / Arm / Pi
400mbit+ usable performance when directly next to the router
lowest possible power draw

So what m2 pcle cards do you recommend for my project?

I have this card running:


I don't know if the card does both modes at the same time because i only tried it at 5GHz as repeater

AsiaRF's m.2 card has DBDC - it will do 2.4 and 5GHz at the same time. I'm not sure if it's low power enough for you.

just curious is there sth from the more known brands like intel or mediatek?

The AsiaRF card is Mediatek.
Avoid intel at all cost, when the use case is AP.


I am curious, did you get it running on an RPi CM4 board?

No only in a X86 CyberOam CR25Wing with Minipcie / M2 adapter MT7921

I use only in repeater STA mode ( without AP ) speed 300/300Mbits

Tested just athis time & no problem in STA 5 Ghz + AP mode but only in 2.4 Ghz

WIth a MiniPci-e MT7612E i have better results 450/300 Mbits

That's good to know. The reason I asked, is that the last time (July 2022) that I tried using an MT7921K adapter in a CM4 router board that I designed, I did not get very far: I kept getting the error below in my log

root@OpenWrt:~# dmesg | grep mt
[    7.317721] mt7921e 0000:03:00.0: enabling device (0000 -> 0002)
[    7.341238] mt7921e 0000:03:00.0: ASIC revision: 79610010
[    7.431616] mt7921e: probe of 0000:03:00.0 failed with error -12

I did not have much time to screw around with it, so I bought and tried 5 different WiFi adapters:

  • Qualcomm QCA6174a Wi-Fi/Bluetooth SoC | 802.11ac Wi-Fi 5 Wireless Network Adapter
  • Qualcomm Atheros QCNFA364A Wireless 802.11ac 867Mbps Bluetooth 4.1 WIFI NGFF/M.2 Card
  • Wi-Fi 6 MediaTek MT7921K NGFF M.2 WiFi Card Dual Band WiFi Bluetooth 5.2 Adapter
  • Intel Dual Band Wireless AX200NGW - WiFi 6 AX200 WiFi Adapter
  • REALTEK RTL8822BE Wireless 802.11AC WLAN Bluetooth 4.2 WiFi Card

Only the Intel and Realtek cards worked reliably.

I needed just one of them to support AP mode (with OpenWrt of course) in the 5GHz band, and luckily, the Realtek card did just that.

My CM4 router has two (2) 1Gbit Ethernet interfaces (WAN and LAN) and an M.2 socket Key E for a WiFi adapter. My router is overkill for the level of service I signed up for with my ISP: 150mbit down and maybe 10mbit up (I don't recall).
All the cards I mentioned above plug into an M.2 socket Key E.

I am designing the ultimate, or at least formidable RPi CM4 router board (for sale) with two (2) 1Gbit Ethernet interfaces (WAN and LAN), an M.2 socket Key E and M.2 socket Key B so that it's possible to have both WiFi 6 and/or 6E, as well as 4G and/or 5G support.

So the card mentioned here

piques my interest, except that it is not a Key E adapter. I wonder if there is a Key E WiFi 6/6E capable adapter that supports AP mode.