I have been using the Personal Hotspot on my 3GS under iOS 4 very successfully for a number of months. Yesterday I upgraded to iOS 5.0 and now the Personal Hotspot no longer connects with my carrier (Verizon). I have reset network settings back to factory setup and tried again. No joy. I am tethered with a USB and get no Internet connection passed through to my Mac. Since I use this feature a lot, I need to downgrade to the previous version of iOS until Apple gets things fixed. I'm a newbie to this forum so can someone direct me to where I can locate iOS 4 online to perform the downgrade? Thanks!