OTA Image Creation#

Silicon Labs has created a tool for generating OTA images called image-builder. The image-builder generates a '.ota' (over-the-air) file from a .gbl (Gecko Bootloader) file.

Generating a .gbl file#

Simplicity Commander is required to generate a GBL image. Once all changes are made and the client's firmware version has been bumped in the OTA Bootloader Cluster Client Policy component, use the following syntax to generate the GBL image:

# commander gbl create <gblfile>.gbl --app <filename>.s37

For bootloader projects, use the --bootloader argument instead of --app. A more complete list of arguments can be found by using the help argument (i.e. commander --help). More information can be found by visiting GBL Commands in the Simplicity Commander User Guide.

GBL images can be created using --encrypt and --sign options for users looking for secure the firmware. This is covered in the Security section of Advanced Topics.

Generating a .ota File#

Once the GBL has been created, the Zigbee over-the-air (OTA) file can be created by using image builder:

$ image-builder-windows.exe --create <ota_name>.ota --string "ZNet_OTA_Client" --version 3 --manuf-id 0x1002 --image-type 0 --tag-id 0x0000 --tag-file <gblfile>.gbl

The resulting ota file can be loaded onto a server's host to begin the OTA process.

More information on this tool, including the --help output for all options, can be found in AN716: Instructions for Using Image Builder.