Apple’s 3.1 Firmware broke compatibility with Redsn0w, meaning that your external GPS units, video cameras, and a whole fleet of other operations have been rendered unusable. However, the Dev Team are back at work and have released three tools which are available only for the iPhone 2G, 3G, and iPod touch 1G. It is important to note which you need and if your hardware is compatible. Their instructions are outlined after the gap.
There is a lengthy thread about it at the Apple Discussion forum and quite a few upset 3GS users. The simple truth is that the progeny of the iPod and a telephone is plagued by none other than poorly implemented system sounds. What has been characterised as ‘whiny’ and ‘squeaky’ is an issue with feedback between the mic and speakers. For the moment, manual fixes are possible by tweaking the volume of both the mic and speakers, but nothing so Apple-esque that it ‘just works’. Apparently, the Apple Store ‘Genius Bar’ has been soused in Apple’s extra fizzy drink as they are mum about Apple’s mistaken programming, citing rather, faulty hardware, thus delivering the problem into the hardware manufacturers.