Google posted an update to the Android Open Source Project’s files last Wednesday, making available the Android 4.0.4 code. In addition to the source release, Google prepared 4.0.4 ROMs for its flagship devices, including the HSPA+ version of the Galaxy Nexus. Users who have gone ahead with the update are now reporting running into some unexpected problems, with their phones struggling to maintain a cellular connection when idle.
There’s an extensive thread of users discussing connection problems on Google Code. Users report that when their phone is idle, or goes into standby mode without enough CPU activity going on in the background, the handset’s radio loses its connection, preventing you from receiving calls until the phone wakes back up. Whatever’s causing this, it sounds tied to CPU activity, or perhaps just power consumption, as rooted users who modify their processor’s clock speed to not drop so low while idle don’t run into the issue. Of course, doing that is going to chew through your battery a whole lot faster, so it’s not a permanent solution.
Google employees have been posting to the thread, and they’re definitely aware of the issue, so for now we’ll just have to wait patiently for an official fix to arrive, or at least until someone comes up with a more graceful work-around.