Applying custom software image updates to non-volatile storage in a failsafe manner

In a computing device, the computing device including a processor and system memory, a method implemented by the computing device, the method comprising:

• the processor breaking an operating system image into separate updateable partitions comprising a kernel partition and a system partition;
• and
• updating at least the kernel partition in isolation with respect to another partition by building a replacement image for the kernel partition and writing the replacement image over an existing image in the kernel partition, and updating the system partition with an update procedure that includes applying update data to a plurality of components of the system partition and validating the resulting updated components, wherein if the components are successfully validated they are committed to the system partition.

A computer program product for use at a computing device, the computing device comprising one or more computer-readable storage media having stored thereon computer-executable instructions which, when executed by a processor, cause the computing device to perform a method comprising:

• breaking an operating system image into separate updateable partitions comprising an kernel partition and a system partition;
• and
• updating at least the kernel partition in isolation with respect to the system partition by building a replacement image for a kernel partition and writing the replacement image over an existing image in the kernel partition, and updating the system partition with an update procedure that includes updating components of an image file system associated with the system partition and simulating an update process before committing updates the resulting updates to the second partition wherein simulating the update process comprises calculating a checksum for the replacement updates and verifying the resultant checksum against a known checksum for a properly built replacement component.

In a computing device, the computing device including a processor and system memory, a system comprising:

• a boot mechanism for the processor to boot the computing device;
• and
• an update loader to which the boot mechanism boots upon detection of a pending update, the update loader comprising the only entity in the device code having write access to protected storage of the device, the protected storage containing at least two partitions comprising a kernel partition and a system partition, wherein the update loader separately updates each partition by building a replacement image for a kernel partition and writing the replacement image over an existing image in the kernel partition, and updates the system partition with an update procedure that includes building a replacement image for the system partition and simulating an update process before committing updates to the system partition, wherein simulating the update process comprises calculating a checksum for the replacement image and verifying the resultant checksum against a known checksum for a properly built replacement image.