List of supported mPCIe modules

This document contains a list of supported WiFi and LTE modules in mini PCI Express card form factor. Document intends to present limitations of the modules and quirks necessary for their flawless operation.

The list is currently limited only to tested and verified modules

LTE modules

Note: By default, in apu3/4, the SIM card slots are "crossed", that is to say, the left SIM slot is wired to the mSATA slot and the right SIM slot is wired to the mPCIe2 slot. You can swap the SIM slots on the fly using GPIO 410 - follow the GPIO documentation for detailed instructions.

Quectel EP06

This LTE module has certain problems with detection in the operating systems. The module uses a USB interface to communicate with the processor and OS. Due to the availability of USB 2.0 and USB 3.0 interfaces in the module, it often gets enumerated incorrectly. The presence of USB 3.0 lanes causes the module to use the USB 3.0 protocol instead of the USB 2.0 protocol. The mPCIe slots on apu boards have only USB 2.0 signals routed to the connectors. In place of the USB 3.0 signals, apu boards have either PCIe signals or SATA signals for WiFi and mSATA modules respectively. The design of the modules is intended to support majority of the modules, but it will not always be compatible with all possible modules, please take it into consideration.

Symptoms of the wrong detection:

only 1 ttyUSB node created by OS
no ttyUSB nodes created by OS
errors in USB enumeration for the module in dmesg

Solutions:

Contact PC Engines for a module firmware update with USB 3.0 protocol disabled if You have problems with module detection.
Cover USB 3.0 signals on the module with tape to block signal connection as shown in the picture:

Quectel EP06 pinout

Black pins mean that they have to be covered with tape. The 6 black pins on the top side are USB3.0 signals. Two pins on the bottom side are I2C/SMBus pins which also should be covered with tape. The module design requires pull-ups on the mainboard side, but they are not present on apu.

Compatible slots:

Platform	mPCIe1	mPCIe2	mSATA
apu2	✔	✔	✖
apu3	✖	✔	✔ ¹
apu4	✖	✔	✔ ¹

(1) Do not forget to enable EHCI0 controller in sortbootorder

For each port's capabilities please refer to mPCIe port capabilities

HUAWEI ME909u

This module works fairly well with all apu boards. But be aware that due to its buggy firmware, LTE may not work in some conditions with the default cdc_ether driver selected by usb_modeswitch. You may have more success using the qmi_wwan driver (echo Configuration=1 >/etc/usb_modeswitch.d/12d1:1573) which implements a workaround in qmi_wwan_rx_fixup().

Compatible slots:

Platform	mPCIe1	mPCIe2	mSATA
apu2	✔	✔	✖
apu3	✖	✔	✔ ¹
apu4	✖	✔	✔ ¹

(1) Do not forget to enable EHCI0 controller in sortbootorder

HUAWEI ME906s M.2

There is an option to use the M.2 Key B to Mini PCIE PCI-E Adapter Converter for 3G/4G/5G and connect Huawei ME906s M.2 4G to compatible mPCIe slot. This adapter includes routing the SIM signals so APU SIM slot may be used without problems.

Kudos to Jamie Lentin (@lentinj) for checking this.

M.2 Key B to Mini PCIE PCI-E Adapter Converter

HUAWEI ME906s

Compatible slots:

Platform	mPCIe1	mPCIe2	mSATA
apu2	✔	✔	✖
apu3	✖	✔	✔ ¹
apu4	✖	✔	✔ ¹

(1) Do not forget to enable EHCI0 controller in sortbootorder

WiFi modules

WLE200NX

This module works fairly well with all apu boards. The module may have issues with interrupts. Related issues:

Compatible slots:

Platform	mPCIe1	mPCIe2	mSATA
apu2	✔	✔	✖
apu3	✔	✖	✖
apu4	✔	✖	✖

Quirks:

The real culprit of interrupt routing problems is the ath9k kernel module responsible for WLE200NX operation. The module has no robust interrupt implementation and tries to remap legacy INTx interrupt with IOMMU which is not possible due to technical reasons. The correct solution is to force ath9k kernel module to use MSI interrupts which can be remapped. This can be done with:

echo "options ath9k use_msi=1" | sudo tee -a /etc/modprobe.d/ath9k.conf

When the module is loaded, it initializes interrupts coming from WiFi devices to be a MSI type. MSI interrupts are correctly remapped by kernel with IOMMU, thus the issue is not present.

Other solutions with kernel command line options:

amd_iommu=off - disables the use of IOMMU in kernel.
intremap=off - disables security feature of IOMMU called interrupt remapping.

WLE600VX

This module works fairly well with all apu boards. Tested by PC Engines and apu users.

Compatible slots:

Platform	mPCIe1	mPCIe2	mSATA
apu2	✔	✔	✖
apu3	✔	✖	✖
apu4	✔	✖	✖

Quirks:

Sometimes the module may have problems with OS communication on mainline releases. In such case providing amd_iommu=off to kernel command line may help.

WLE900VX

This module works fairly well with all apu boards.

Compatible slots:

Platform	mPCIe1	mPCIe2	mSATA
apu2	✔	✔	✖
apu3	✔	✖	✖
apu4	✔	✖	✖

Quirks:

Sometimes the module may have problems with OS communication on mainline releases. In such case providing amd_iommu=off to kernel command line may help.

WLE1216V5-20

Correct detection of this module is a little tricky and hardware related. Due to different PCI Express reset circuit on apu boards, apu2 has problems with this particular module detection. Most likely due to different reset timing caused by different PE_RST circuitry on apu2, the module does not come out of reset in time during PCI enumeration and thus is not detected in BIOS and operating system.

Quirks:

On apu2 in mPCIe2 slot module works only after a soft reboot with legacy firmware, however during the tests we have encountered kernel panics. On the other hand users did not experience kernel panics and are able to use the module after reboot. The apu2 board revision plays a huge role in the mentioned problems.
on apu3 and apu4 the module works with any firmware and does not require reboot

Platform	mPCIe1	mPCIe2	mSATA
apu2	✖	✔ ¹	✖
apu3	✔	✖	✖
apu4	✔	✖	✖

(1) Refer to quirks, it is known to not work stably on all apu2 board revisions

AW7915-NP1

The AW7915-NP1 is a MediaTek MT7915E based Wi-Fi 6 (802.11ax) card from AsiaRF. It features 4x4 MIMO and support for 160MHz channels, and a maximum theoretical bandwidth of 2400 Mb/s. In the apu2, the card can reach over 1Gb/s transfer speeds in ideal conditions.

This module has been tested to work reliably in an apu2c4 board running OpenWRT 21.02.02. No firmware tweaks are necessary for correct operation.

The card gets hot under sustained operation, easily reaching over 130 degrees celsius if not cooled sufficiently. A heatsink is recommended, the card does not come with one.

Platform	mPCIe1	mPCIe2	mSATA
apu2	✔	✔	✖
apu3	✔	✖	✖
apu4	✔	✖	✖

Ethernet controllers

Dual Ethernet Controller Realtek RTL8111

RTL8111

Compatible slots

Platform	mPCIe1	mPCIe2	mSATA
apu2	✔	✔ ¹	✖
apu3	✔	✖	✖
apu4	✔	✖	✖

(1) If RTL8111 is attached to mPCIe2 slot then option force mPCIe2 slot Clk in Payload menu must be enabled

This model works well with apu1 boards. However, on apu2, apu3 and apu4 platforms following steps should be done to correctly enable it:

On apu2 board (apu1, apu3 and apu4 boards aren't affected) make sure to enable option force mPCIe2 slot Clk in Payload menu if you attached module to mPCIe2 slot. This menu is available during boot process by pressing F10 button. In OS now, you should be able to see your Ethernet controller under PCI devices.
Manually download and install missing Realtek firmware. Even if Ethernet controller is recognized by OS it won't work correctly without it. Installation can be done, for example in Debian OS, by performing those steps:
- Edit /etc/apt/sources.list file. It should contain additional two lines:
```
deb http://ftp.pl.debian.org/debian stretch main non-free
deb-src  http://ftp.pl.debian.org/debian stretch main non-free
```
- Update apt-get:
```
sudo apt-get update
```
- Install Realtek firmware
```
sudo apt-get install firmware-realtek
```

SATA controllers

ASMedia ASM1061

Module is NOT SUPPORTED by PC Engines apu platforms. ASM1061 was tested with Delock 95233 mPCIe 2xSATA module.

ASM1061

Compatible slots

Due to apu boards construction, it is possible to test that module only under apu2 mPCIe2 slot. Capacitors placed near the mPCIe1 slot prevent connecting the SATA cables to the module. Therefore, module was tested only in mPCIe2 slot. After multiple tests performed, it turned out that ASM1061 module is not supported by PC Engines apu2 platform.

Tests results

Carried out tests and their results are presented in debug documentation. Detection problem is described more precisely there. Also, possible reasons of ASM1061 behavior are presented. Anyway, in every case and configuration that module doesn't work properly.

Other hardware fixes

A good source of hardware fixes information of Your board is the PC Engines site.

If You think Your problem may be related to issues listed here, contact PC Engines for details.

If You have not found a solution either after reading this document or contacting PC Engines, feel free to open GitHub issue.

apu2

Set of changes for apu2:

Version apu2d:

Reduce leakage current between V3 and V3A power rails (can cause problems with SD cards).
Add options for better compatibility with LTE modem modules.

Version apu2c:

Integrate blue wire patches (EMI, power-up circuit) into PCB fab.

apu3

Set of changes for apu3:

Version apu3c:

Improve compatibility with LTE modem modules: Disconnect SMB_DAT / SMB_CLK signals (1.8V level on Quectel).
Improve compatibility with LTE modem modules: No stuff diodes D4 / D17, option resistor bypass (extremely low VIL on Huawei modems, sensitive to incoming EMI).
Optional SIM presence indicator / SIM card detect.
Disable non-functional NCT5104D watchdog timer.
Increase 3.3V current limit to allow for two simultaneous LTE modems.
Some DFM changes.

Version apu3b:

Fixed USB header J13 pinout.

Version apu3a:

The pinout on USB header J13 is wrong, do not use.

apu4

Set of changes for apu4:

Version apu4c:

Minimize leakage from V3A to V3 rail (SD card compatibility)
Fix USB header J12 pinout.
Change SIM switch to FXLA2203, FXLA2204 went EOL.
New 2GB version apu4c2, single SIM socket.
Optional 10 pin LPC header to allow for future TPM option.