Apple update shuts down some hacked iPhones

Apple Inc. has issued a software update that creates problems for iPhones modified to work with a cellular carrier other than AT&T Inc. and disables at least some unofficial programs installed on other iPhone handsets. Apple warned earlier this week that the iPhone update - which adds access to the iTunes Wi-Fi Music Store and fixes some security flaws - could permanently disable phones running programs that untether phones from its exclusive partner's network.