I'm on an iMac and I am trying to update my jailbroken iPhone 4 from 4.0.1 to 4.1, then re-jailbreak. I have no reason to keep my current baseband (no unlock needed and a new one is one the horizon), but the latest version of TinyUmbrella automatically changes the hosts file to point to cydia's servers. I'm trying to change it back to the original by deleting the last line in the file, but it won't let me save it when I am am done. I have gone to "Get Info" and given myself Read & Write privileges, yet it still won't let me. Am I missing something here? I have searched all over and haven't found an answer. Any help would be greatly appreciated. Thanks.