Wi-Fi Overview and Drivers

The Reference Operating System for IoT (Ref-OS-IoT) provides these Wi-Fi* features:

  • 802.11 a/b/g/n/ac support
  • WPA and WPA2, 802.1x
  • Support Dual band (2.4 & 5 GHz)
  • Wi-Fi* Direct


Firmware and Drivers

Ref-OS-IoT provides the open source Linux kernel drivers; the drivers load the Wi-Fi* firmware during boot time.

This can be seen in dmesg with following line:

[   24.641377] iwlwifi 0000:01:00.0: loaded firmware version 27.455470.0 op_mode iwlmvm

Firmware is searched from /lib/firmware and the driver automatically selects the latest if multiple firmware versions are available.

root@intel-5xx-64:~# ls -la /lib/firmware/iwlwifi-8000C-*.ucode
    1 root     root       1745176 Mar  8 00:45 /lib/firmware/iwlwifi-8000C-13.ucode
    1 root     root       2351636 Mar  8 00:45 /lib/firmware/iwlwifi-8000C-16.ucode
    1 root     root       2383144 Mar  8 00:45 /lib/firmware/iwlwifi-8000C-19.ucode
    1 root     root       2394060 Mar  8 00:45 /lib/firmware/iwlwifi-8000C-21.ucode
    1 root     root       2120860 Mar  8 00:45 /lib/firmware/iwlwifi-8000C-22.ucode
    1 root     root       2227284 Mar  8 00:45 /lib/firmware/iwlwifi-8000C-27.ucode

Files Copied to Root

The following binary/configuration files are copied onto root of the file system:

Chipset firmware 


Kernel module configuration file used when inserting the kernel driver with the command modprobe.  


Driver module


Configuration file for wpa_supplicant


Driver Modules

To list driver modules, enter following:

$ lsmod

To load the driver module, enter the following:

$ modprobe iwlwifi

To remove the driver module, enter the following:

$ modprobe –r iwlwifi

This powers down the chipset, if it is not already powered down.

Manually powering Wi-Fi up or down

If the ifconfig command lists the wifi interface in its results, Wi-Fi is powered up. If it does not, Wi-Fi is powered down. The wireless chipset can be powered up or down with these commands:

rfkill unblock wifi
rfkill block wifi

From a terminal, use the ifconfig command to check if the network interface is configured


Note:The rfkill unblock/block wlan command is generally used to power up/down the WLAN.


For more complete information about compiler optimizations, see our Optimization Notice.