A number of both first- and second-generation iPod touch users are reporting Wi-Fi irregularities after installing iPhone OS 3.0. No less than four separate threads on Apple’s Discussion boards mention Wi-Fi problems, the most common of which seems to be the iPod touch failing to reconnect to the most recent network after going to sleep, forcing the user to manually reconnect each time.
Some users have reported that resetting the network settings fixes the problem; others report that this fails to solve the issue. One iLounge editor has experienced problems on first- and second-generation iPod touches, with a reset of network settings working on the iPod touch 2G, and the same thing on the iPod touch 1G resulting in the device failing to sense its own Wi-Fi chip, displaying a “No Wi-Fi” message afterwards.
Other users have reported more mild problems, such as reduced Wi-Fi signal, or difficulty in getting their devices to reconnect following installation.