USB mode switching

Our AX1L, AX4L and AX5L adapters have a dual mode functionality. Before installing our drivers, they act like flash storage, which contains the Windows drivers in it. After the drivers are installed (in any OS), they switch to normal Wi-Fi adapter mode. USB adapters that support this dual functionality are called “multi-state”, “ZeroCD” or “Virtual CD-ROM” devices.

In Linux, multi-state devices may bump into two issues:

Adapter isn’t switched to WLAN mode

Normally, the /lib/udev/rules.d/40-usb_modeswitch.rules file is responsible to call the usb_modeswitch command and switch the adapter to WLAN mode. To check if the adapter has been switched to WLAN mode, run:

lsusb | grep 0bda

# This output means it was properly switched to WLAN mode:
Bus 001 Device 009: ID 0bda:b832 Realtek Semiconductor Corp. 802.11ac WLAN Adapter

# While this output means it was NOT switched to WLAN mode:
Bus 001 Device 003: ID 0bda:1a2b Realtek Semiconductor Corp. RTL8188GU 802.11n WLAN Adapter (Driver CDROM Mode)

If you have an older distribution that doesn’t switch the adapter to WLAN mode, you may use the following command to switch it manually:

sudo /usr/sbin/usb_modeswitch -KQ -v 0bda -p 1a2b

If you verified that this command works, but you need to execute it manually after every boot, then run the following commands to automate it:

sudo -i
echo 'echo ACTION=="add", ATTR{idVendor}=="0bda", ATTR{idProduct}=="1a2b", RUN+="/usr/sbin/usb_modeswitch -KQ -v 0bda -p 1a2b"' >/etc/udev/rules.d/50-custom.rules
update-initramfs -u
reboot

Boot delays

In rare circumstances, it’s possible that the Linux boot or shutdown process may delay for a long time while trying to access that “flash storage”. To check if that’s the case, remove the adapter from the USB slot and see if the delay is gone.

Normally, installing our driver and using an up to date distribution should avoid this issue, but if it happens, the following command line parameter can be added in grub to completely ignore the flash storage mode:

usb-storage.quirks=0bda:1a2b:i