Source: http://forum.xda-developers.com/showpost.php?p=53739230&postcount=5031
Finally I was able to block the SystemUpdateService wakelock, using this app:
Autorun Manager
go to settings, enable the option to show system entries
find google play services and disable:
SystemUpdateService$Receiver
SystemUpdateService$ActiveReceiver
SystemUpdateService$SecretCodeReceiver
done… no more wakelock and it didn't break anything, syncs all work ok
I know this app doesn't look the best, but I tried others like “Android Tuner Free”, “Disable Services”, “Gemini App Manager”, etc, but they allowed me to only disable the main service and didn't show the other receivers that had to be disabled.