Understanding OTA Firmware Update

Windows Mobile 6.5
4/8/2010

A Windows Mobile device does not have a single firmware, but instead has ROM regions segmented into different ROM packages that can be individually updated. Over-the-air (OTA) Firmware update is a way to update the ROM packages in a device by using the Image Update technology and Open Mobile Alliance Device Management (OMA DM) version 1.2.

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Settings updated through Image Update persist after cold boot; over the air provisioned settings persist after a warm boot, but do not persist after a cold boot.

The OTA firmware update process can be automated. An OMA DM server initiates this process and it involves interaction between the DM server, the OMA DM client and the Download Agent image update installer on the client device.

Using the Image Update technology, the Original Equipment Manufacturer (OEM) creates update packages for various ROM versions. The packages contain provisioning XML created by an OEM or Mobile Operator. Completed packages must be signed, and are stored in the OMA DM server or in a connected database.

The manner in which the update package will be downloaded depends on the delivery channel established between the OEM and Mobile Operator. Typically, the Mobile Operator has a firmware update server set up to deliver packages to the device. The OEM would send the update package to the Mobile Operator directly so that it can be put on a Web site hosted on the Mobile Operators server. The Mobile Operator then uses an OMA DM server to initiate communication between the device and the server so that the package can be downloaded. Other scenarios are possible.

After the device has downloaded an update, XML files are processed by the FwUpdate Configuration Service Provider. The FwUpdate Configuration Service Provider updates the firmware (ROM) and sends status to the OMA DM server. The update packages can be processed either during cold boot or during the Image Update process.

  • During cold boot all files in all packages are processed.
  • During the image update process, only files in packages that have been updated will be processed.

In both cases, Configuration Manager processes the XML files. This process is further described in OTA Firmware Update Architecture and OTA Firmware Update Scenarios.

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