Do you mean?
Did you mean to say "Apple admits to these hardware defects built-in to the iPhone4"?
Because I don't think they have.
Also, I noticed earlier today a new thread starting on some message boards about a fix. Turns out that these people were using standard SIMs that they had cut down themselves rather than proper micro-SIMs.
Someone noticed that their cut-down SIM leaves two of its contacts exposed on one edge and that they appeared to be shorting on the metal of the SIM holder. A small piece of tape on the holder solved his problem and a number of other people are jumping in to say it's solving their problem too.
If that *is* the problem, then the fault is only indirectly with Apple for having a metal SIM holder, but then it's not meant to be used with home-made SIM cards.