With over 6 million downloads since its release a short time ago, Apple's new iPhone OS 3.0 update is certainly proving popular. If you’ve read any iPhone 3G S reviews, you also know that the new firmware is designed to take advantage of the latest hardware, but works with the original and 3G iPhone as well. There are scattered reports, however, that the picture isn't as rosy when paired with these older models, with users complaining that it is causing the battery life on their phones to take a nosedive.
The reports aren't isolated, and some users are even reporting that the update causes their phone to run hot on top of having a shortened battery life. During the iPhone OS 3.0 beta, there were a few reports of battery life drops, which were primarily attributed to debugging software. Given that this is a final release, you wouldn't expect the two to be related. Nevertheless, if there is an issue, hopefully we'll hear from Apple soon on potential resolutions. The newer-hardware 3G S is apparently unaffected.