The iPhone 3.1.2 update that Apple delivered to iTunes weighs in at 241Mb and includes fixes for a sporadic issue which may cause the iPhone not to wake up from sleep mode reports an article over on phonenews
Another bug fix deals with an intermittent issue which interrupts mobile services until a restart is done, and another bug fix that solves an issue which could cause occasional crashing when video streaming.
iPhone 3.1.2 also includes new carrier settings for AT&T which is thought to break any jailbreak applied to the iPhone and any tethering functionality.