MAC address randomization is a feature that has been around for some years and is used to help defeat privacy tracking tools. The concept is simply this; the MAC address provided to a given WiFi network is randomized, making it difficult to track a system based on what used to be an immutable MAC address.
While many modern network cards today support enabling this feature on WiFi networks, some WiFi network cards either don’t or don’t enable it by default.
One among these is the Marvell Avastar card present on most, if not all generations of Microsoft Surface devices. Once enabled, you’ll see the expected “Use random hardware address” toggle in the WiFi properties under “Network & Internet.”
While this setting was present at one point, a Microsoft firmware update caused it to revert to a disabled state however the following steps can restore that functionality:
- Open Regedit and navigation to the following value: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\mrvlpcie8897
- Rightclick on MACRandomization and change the value to “00000001” (that’s right, seven zeros followed by a one) to enable this feature
- Restart your Surface Pro, Surface Laptop, or Surface Book
- Once restarted, open your WiFi configuration screen and you should now see the “Use random hardware address” toggle