It is only 3G users of the yellowsn0w unlock that need to avoid the update.
In fact, until a lower-level ("hard") unlock comes out, yellowsn0w users should *always* avoid official updates -- they should only update through custom firmware IPSWs made through our various pwnage tools. These custom IPSWs can update your main firmware without updating your baseband (which would kill the yellowsn0w injection exploit).
by MuscleNerd
blog.iphone-dev.org/post/73554…(this.href);return false;
[center]das iPhone 4 bei O2[/center]