UpdateOS

Update OS

Microsoft Windows 的版本
操作系统系列	Windows NT 系列
体系结构	ARM32 (ARMv7), ARM64 (ARMv8), x86, AMD64
MobileCoreUpdateOS OneCoreUpdateOS

Update OS is a lightweight version of the Windows operating system that performs servicing operations for Windows Phone- and Windows Core OS-based system images. It makes use of a minimal version of the Windows component-based servicing stack (CBS) and runs inside of a bootable WIM image, allowing changes to system partitions to be made while they are not in use. Update OS can be arbitrarily invoked by performing a system reset, installing a system update, or by forcing a device running the FFULoader EFI application to boot into a specialized version of Update OS with support for FFU flashing operations.

Functionality

Updates are distributed via the Windows Update service as cabinet packages using the following suffixes:

• .spkg, .spku and .spkr - old Windows Phone 8-style SPKG update delivery method
• .cbs, .cbsu and .cbsr - utilizes the modern Windows CBS stack to install feature updates and optional components on-demand, since Windows 10 Mobile

Canonical packages (.spkg/.cbs) consist of complete components, whereas Delta (.spku/.cbsu) and Recall packages (.spkr/.cbsr) simply update and remove their target features, respectively. Most internal Windows 10 Mobile self-hosting builds were released to beta testers through the public Windows Update infrastructure, although these were only installed if the host device had a specific "super secret registry key" (SSRK) installed. Some builds (such as build 14314) additionally depend on the presence of the Microsoft.Tools.StudyID1510 feature to install. If a build is pushed to a device without it installed, the servicing stack will fail to process the update due to failing dependency checks.

Since the Windows Phone 8 GDR3 update and Windows Phone 8.1, overall progress is additionally reported during update operations. Support for CBS-based updates were added as part of the original Windows 10 Mobile release. The operating system will attempt to reboot and retry the servicing operation if it encounters an error. Updates can also be delivered to the underlying operating system through an external SD card; a feature that was primarily used on devices with as little as 4 gigabytes of on-board storage. Attempting a system reset on any Windows Phone device will cause Update OS to delete all local user data and restage the operating system from scratch, using the packages present in the pre-existing OS component store.

Some Windows Phone self-host images may optionally come with a specialized version of Update OS for the sole purpose of flashing their respective FFU images. These images can be booted by having the target device run the FFULoader EFI application, while the host machine invokes the FFUTool command-line utility with argument -wim, passing in a path to a valid WIM image. This specific version of Update OS features USB device descriptors for the FFU flashing interface to ensure compatibility with the FFULoader and FFUTool applications.

The Update OS image files used for the spinning gear animation, progress bar and update failure image are raw DirectDraw Surface textures, stored in the \Windows\System32\UpdateImages, \Windows\System32\ProgressImages and \Windows\System32\ErrorImages directories.

Gallery

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  Gear animation

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  FFU flashing mode

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  External storage mode

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  Update failure