As you can find on SOTI documentation, there's a nice support in the scripting language.
Then I got a request on how to send this intent:
am start -n com.zebra.customupdater/.UpdaterActivity --es "package" "/storage/sdcard1/SPR31256.zip" it works
This became:
sendintent -a "intent :x Intent;action=android.intent.action.MAIN;component=com.zebra.customupdater/.UpdaterActivity;S.package=/storage/sdcard1/SPR31256.zip;end;"