Update windows-autopatch-hotpatch-updates.md

Adding important device OS prerequisites that prevent devices from installing updates and not being secure.

windows/deployment/windows-autopatch/manage/windows-autopatch-hotpatch-updates.md

@@ -1,7 +1,7 @@
 ---
 title: Hotpatch updates
 description: Use Hotpatch updates to receive security updates without restarting your device
-ms.date: 12/17/2024
+ms.date: 11/19/2024
 ms.service: windows-client
 ms.subservice: autopatch
 ms.topic: how-to
@@ -30,25 +30,38 @@ Hotpatch updates are [Monthly B release security updates](/windows/deployment/up
 - No changes are required to your existing update ring configurations. Your existing ring configurations are honored alongside Hotpatch policies.
 - The [Hotpatch quality update report](../monitor/windows-autopatch-hotpatch-quality-update-report.md) provides a per policy level view of the current update statuses for all devices that receive Hotpatch updates.
 
+## Operating system configuration prerequisites 
+To prepare a device to receive hotpatch updates, configure the following device-side operating system settings. Failure to configure these settings will result in the device not being offered the hotpatch update or being unable to apply all the hotpatch updates, leaving some vulnerabilities unmitigated.
+
+### Virtualization based security (VBS)
+VBS must be enabled for a device to be offered hotpatch updates. For information on how to set and detect VBS enabled, see [Virtualization-based Security (VBS)](https://learn.microsoft.com/en-us/windows/security/hardware-security/enable-virtualization-based-protection-of-code-integrity?tabs=security).
+
+### Arm 64 devices must disable compiled hybrid PE usage (CHPE) (Arm 64 CPU Only)
+The following requirement only appies to Arm 64 CPU devices when using hotpatch updates. Hotpatch updates are not compatible with servicing CHPE OS binaries located in the %SystemRoot%\SyChpe32 folder. In order to ensure all the hotpatch updates take effect, you must set the CHPE disable flag and restart the device to disable CHPE usage. You only need to set this flag one time. The registry setting will persist through updates. To disable CHPE, set the following registry key:
+Path: **HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management**
+Key value: **HotPatchRestrictions=1**
+
+> [!IMPORTANT:]
+> This setting is required becuase it forces the operating system to use the emulation x86-only binaries insetad of CHPE binaries on Arm 64 devices. CHPE binaries include native Arm 64 code to improve performance so you excluding them may impact performance or compatibility. Be sure to > test application compatibility or performance impacts before rolling out hotpatch updates widely on Arm 64 CPU based devices.
+
+If you choose to no longer use Hotpatch updates you can clear the flag (HotPatchRestrictions=0) and restart the computer which will reenable CHPE usage.  
+
 ## Eligible devices
 
 To benefit from Hotpatch updates, devices must meet the following prerequisites:
 
 - Operating System: Devices must be running Windows 11 24H2 or later.
-- VBS (Virtualization-based security): VBS must be enabled to ensure secure installation of Hotpatch updates. For more information on how to set and detect if VBS is enabled, see [Virtualization-based Security](/windows/security/hardware-security/enable-virtualization-based-protection-of-code-integrity?tabs=security).
+- VBS (Virtualization-based security): VBS must be enabled to ensure secure installation of Hotpatch updates.
 - Latest Baseline Release: Devices must be on the latest baseline release version to qualify for Hotpatch updates. Microsoft releases Baseline updates quarterly as standard cumulative updates. For more information on the latest schedule for these releases, see [Release notes for Hotpatch](https://support.microsoft.com/topic/release-notes-for-hotpatch-in-azure-automanage-for-windows-server-2022-4e234525-5bd5-4171-9886-b475dabe0ce8?preview=true).
 
-> [!NOTE]
-> Hotpatch is available on Windows Server. For more information, see [Hotpatch for Windows Server Azure Edition](/windows-server/get-started/enable-hotpatch-azure-edition).
-
 ## Ineligible devices
 
 Devices that don't meet one or more prerequisites automatically receive the Latest Cumulative Update (LCU) instead. Latest Cumulative Update (LCU) contains monthly updates that supersede the previous month's updates containing both security and nonsecurity releases.  
 
 LCUs requires you to restart the device, but the LCU ensures that the device remains fully secure and compliant.
 
 > [!NOTE]
-> If devices aren't eligible for Hotpatch updates, these devices are offered the LCU. The LCU keeps your configured Update ring settings, it doesn't change the settings.<p>For **ARM64 devices**, Compiled Hybrid PE Usage (CHPE) is turned on by default. You must turn off CHPE to receive regular LCU to keep your ARM64 device compliant and secure.</p>
+> If devices aren't eligible for Hotpatch updates, these devices are offered the LCU. The LCU keeps your configured Update ring settings, it doesn't change the settings.
 
 ## Release cycles