The most vexing issue that's arisen thus far is the occurrence of random reboots: Some users are finding that their devices suddenly restart during both active use and idle time, with no warning and for no apparent reason.
I didn't experience this phenomenon while I was testing a pre-release version of Android 4.2 on the Nexus 4 and Nexus 10 some weeks back. I have, however, experienced it sporadically in the days since the platform's debut -- both on upgraded devices like the Nexus 7 and Galaxy Nexus and on some of the new Nexus hardware.
It isn't clear how many users the glitch is actually affecting, but it's enough to make a decent amount of noise. A quick search of the Web turns up numerous threads discussing the Android 4.2 random reboot issue, both within Google's official Android issues site and within enthusiast forums like XDA Developers.
The good news is that help is on the way: I've confirmed with Google that the Android team is aware of the issue and has pinpointed the problem -- and that a fix will be included in the next incremental release.
So what's actually going on here? Officially, Google has yet to divulge any details about the nature of the glitch. We can, however, use the data in front of us to make some educated guesses.
Android 4.2 random reboots: Tracking down the cause
Let's start with the obvious: A lot of users reporting the Android 4.2 reboots have noticed a correlation between reboots and the presence of HD Widgets, a popular and highly rated widget utility available in the Google Play Store. Some users observed that uninstalling HD Widgets seemed to stop the random reboots from happening, which led to a theory that HD Widgets might be the culprit.
That theory is not entirely accurate -- but it is an important piece of the puzzle. First off, if you read through the various bug reports, it's clear that even though HD Widgets is a common variable, it is not absolute; there are users who are experiencing random reboots and don't have HD Widgets installed. That alone tells us there's something bigger at play.
Second of all, members of the HD Widgets development team say they've talked to Google about the crashes. Google, they say in the "User Reviews" section of their Google Play Store page, confirmed to them that the app itself is not to blame and that the bug resides on the OS level.
That makes sense for a couple of different reasons. Given the architecture of the Android platform, it shouldn't be possible for a single app to take down an entire system in the first place, no matter how badly it fails; at worst, an app would cause a force-close error informing the user that its process has "stopped unexpectedly."
Beyond that, some sharp power-users have discovered that disabling Google's location-based services seems to stop the reboots from occurring, with or without HD Widgets in place. This has come up in several places and been replicated by numerous people.
Android 4.2 random reboots: Putting it all together
All combined, the logical conclusion is that Google's location-based services -- GPS and/or mobile network location -- appear to be unstable in certain circumstances with Android 4.2. Apps like HD Widgets access those services on a regular basis, which is likely why they're connected to the issue.
(HD Widgets' user base, incidentally, is strongly skewed toward Android 4.2 -- about 15 percent of the app's 500,000-plus active users are on that version of the platform, according to the developers -- which may help explain why it's been the most frequently noticed commonality among those troubleshooting this issue.)
There may also be a connection to the lock screen widget feature introduced with Android 4.2. HD Widgets was one of the first and most prominent third-party apps to offer support for that functionality. What's more, the lock screen widget feature wasn't available with the pre-release software loaded on review devices, which could explain why I didn't experience this issue during my initial evaluations.
These details, of course, are merely conjecture. But the pieces sure do seem to add up.
Android 4.2 random reboots: The next steps
So what's next? For the moment, there's not much to do other than wait and optionally apply a temporary Band-Aid. Disabling location-based services either within the main Android settings or within the settings of third-party apps that use them seems to be the most reliable workaround, if you're among those experiencing the reboots. Yes, it's far from ideal -- but for now, it's the best we've got.
[UPDATE (12/5/12 7:00 p.m. ET): The developers of HD Widgets have just released an update that they hope may improve the issue as it relates to their app. Long story short, they're implementing a workaround within HD Widgets that prevents the app from using a specific Android service connected to the reboots. The update has been pushed to the Play Store and should be widely available by Wednesday evening.]
With any luck, Google's permanent solution will be here sooner than later. Regardless of how many users it's affecting, I think we can all agree this isn't the kind of issue you'd want to leave unresolved for long.