Microsoft today pushed Windows 10 Mobile Build 15254.489 (10.0.15254.489) as the cumulative update KB4316692 to those on Fall Creators update aka Windows 10 Mobile Version 1709. The changelog for the Build 15254.489 mentions only fixes and security updates. Read the full changelog below.

You can check the update availability by going to Settings–>Update & Security–>Windows update–>Check for updates.

Windows 10 mobile Build 15254.401 Changelog:

This update includes quality improvements. No new operating system features are being introduced in this update. Key changes include:

  • This build includes all the improvements from KB4284874.
  • Addresses a mobile-only issue in which Enterprise files could be saved as Personal files although the Windows Information Protection policy is enabled on the device.

If you installed earlier updates, only the new fixes contained in this package will be downloaded and installed on your device.

 KB4284874 Improvements and fixes:


This update includes quality improvements. No new operating system features are being introduced in this update. Key changes include:

  • Provides support to control usage of Indirect Branch Prediction Barrier (IBPB) on some AMD processors (CPUs) for mitigating CVE-2017-5715, Spectre Variant 2 when switching from user context to kernel context. (See AMD Architecture Guidelines for Indirect Branch Control and AMD Security Updates for more details). For Windows client (IT pro) guidance, follow the instructions in KB4073119. Use this guidance document to enable IBPB on some AMD processors (CPUs) for mitigating Spectre Variant 2 when switching from user context to kernel context.
  • Provides protections from an additional subclass of speculative execution side channel vulnerability known as Speculative Store Bypass (CVE-2018-3639). These protections aren’t enabled by default. For Windows client (IT pro) guidance, follow the instructions in KB4073119. Use this guidance document to enable mitigations for Speculative Store Bypass (CVE-2018-3639) in addition to the mitigations that have already been released for Spectre Variant 2 (CVE-2017-5715) and Meltdown (CVE-2017-5754).
  • Includes additional performance improvements.
  • Addresses a mobile-only issue where enterprise files could be saved as personal files even though the Windows Information Protection policy is enabled on the device.
  • Addresses an issue where firmware updates cause devices to go into BitLocker recovery mode when BitLocker is enabled, but Secure Boot is disabled or not present. This update prevents firmware installation on devices in this state. Administrators can install firmware updates by:
    1. Temporarily suspending BitLocker.
    2. Immediately installing firmware updates before the next OS startup.
    3. Immediately restarting the device so that BitLocker doesn’t remain in the suspended state.
  • Addresses an issue where booting with Unified Write Filter (UWF) turned on may lead to stop error 0xE1 in embedded devices, particularly when using a USB hub.
  • Increased the Internet Explorer cookie limit from 50 to better align with industry standards.
  • Security updates to Internet Explorer, Microsoft Edge, Microsoft scripting engine, Windows Desktop Bridge, Windows apps, Windows Server, Windows wireless networking, Windows storage and filesystems, Windows app platform and frameworks, and Windows virtualization and kernel.

If you installed earlier updates, only the new fixes in this package will be downloaded and installed on your device.