Enabling Unified Write Filter
Our microcontroller boards running Windows 10/11 IoT LTSC offer the option to enable UWF (Unified Write Filter), a powerful feature that can enhance the reliability and security of your device.
What is UWF?
UWF is a feature in Windows IoT LTSC that provides a layer of protection by redirecting all write operations on the system to a virtual overlay. This means that changes made to the system, whether from applications or user data, are not permanently written to the eMMC storage unless explicitly committed. This makes it particularly useful in embedded systems or devices that need to maintain a consistent and reliable state over time.
Why could UWF be useful?
- Protection of eMMC Storage: One of the key benefits of UWF is its ability to protect the eMMC storage. Since writes are redirected to a virtual layer, it reduces the wear and tear on the physical storage, extending its lifespan. This is especially important in industrial or commercial devices that require long-term stability.
- Enhanced Device Stability: By preventing unintended changes to the system, UWF helps to preserve the integrity of the operating system and its configuration. If something goes wrong, a reboot restores the system to its previous state, which helps maintain stability without the risk of corrupting critical files.
- Security: UWF can help prevent unauthorized changes to your system, adding an extra layer of security by ensuring that malicious software or accidental modifications do not impact your device.
How to Enable UWF
Enabling UWF on our F&S board is straightforward:
- Enable Windows Features: Open "Turn Windows Features on or off" and ensure that the checkbox for "Unified Write Filter" under "Device Lockdown" is checked
- Use Command Line: Open a command prompt with administrative privileges
- Enable UWF: Type the following command to enable UWF:
Restart your computer.
NOTE:
By default, the UWF (Unified Write Filter) overlay is configured with a size of 1 GB. If the overlay storage exceeds this size, the system may automatically restart as a protection measure to avoid potential system instability or corruption.
You can adjust the size of the overlay using the uwfmgr.exe tool. To change the overlay size, use the following command:
Replace <size> with the desired overlay size in MB (e.g., 1024 for 1 GB or 2048 for 2 GB).
Make sure to set an appropriate size based on the needs of your application to ensure smooth operation and avoid unexpected system reboots.
