Got a Nexus phone but can’t wait for the over-the-air update process to deliver the latest and greatest operating system to your handset? Simple, clear the service framework data and force the update key. But this is not the right thing to do, Google’s Dan Morrill explains on Reddit
“Doing this changes the primary ID by which Google knows your device. As far as the servers are concerned, the device was basically factory reset. There are many downstream effects of this, but a big one is that this invalidates the tokens used by any app that uses GCM (which is nearly all the Google apps, and a ton of third-party apps.”
This will have adverse effects on different apps. With Play Store you have to log out and log back in, With Gmail usually you won’t get new mail notifications for a while, etc. Some apps you may have to clear data on to recover. All apps will simply stop getting push-messages, until they get a new GCM ID.
It will not brick your device, but it makes a ton of nuisances on the device, including some that can look pretty annoying. So if you are impatient ‘adb sideload’ is a better choice.