Google replaced the Bluetooth stack in 4.2 and effectively destroyed Bluetooth on many devices. Google is now trying to correct the problem and have announced that 4.2.2 will be out shortly, whatever that means, and have a fix.
So I would think that no devices will be getting 4.2 for some time until Google works out its self-caused Bluetooth disaster.
4.2.2 is out for nexus devices. That means the bugs(Bluetooth and WiFi) in the the original OS got a fix so we could expect the update for asus transformer infinity in a month or so. Waiting desperately for it.
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