Since version 3.6.0 it is possible to trigger the installation of a local update from an intent.
To do this the action “com.handheld.updater.action.INSTALL_LOCAL_UPDATE” has to be called with a string extra called “file”.
This needs to point to the ZIP file within the Android OS file system.
See the command below for a full example
am broadcast -a com.handheld.updater.action.INSTALL_LOCAL_UPDATE --es file "/sdcard/ota.zip"