@AC Hardware Faults.
"That's all very well saying that you could reduce the problem by ammending the code to process the signal better when attenuated but what you're basically saying is that they can change the code so that it receives a better signal than previously when the aerial is shorted/covered?"
No, AC, that is not what I am saying. My post didn't state that. I think the issue is that you didn't fully understand what I said, and that might be because you don't come from an electronics/communications background.
I'll try an explain further. A weak signal is a weak signal and you can't fix that by a software mod.
Your assumption is that that you can only deal with this particular defect by a hardware modification. This assumption is wrong.
The weak signal comprises two elements: the signal of interest and noise. Usually what happens is the signal is received by the antenna, amplified and down converted to a lower frequency, often referred to as an IF frequency (internediate frequency).
The goal is to extract the information carrying signal, decode it and obtain a digital data stream from the analogue signal.
The noise is the problem, too much noise on the modulated information carrying signal and the decoded signal will contain too many errors.
What appears to be happening in Apple's case, is that holding the antenna reduces the signal strength which the antenna receives, a weaker signal usually means that the signal is becoming lower in signal strength relative to the noise. If the signal becomes too weak, the noise can dominate and when the analogue signal is demodulated/decoded into digital form, errors result.
So yes, the fundamental cause is a weaker signal from the aerial, but it can be dealt with in software by algorithms intended to reduce the noise and make the extraction of the data from the analogue signal better, with fewer errors.
In fact, there are actually two scenarios.
1)The signal is just too weak in absolute terms to be give a decent output from the RF radio receiver
2)The signal to noise ratio of the RF signal is too low because the signal has become weaker, and this results in errors when decoding/demodulating the data from the analogue signal.
If the IPhone suffers from the first scenario then there won't be much Apple can do about it, other than make some hardware design mods to the antenna and RF circuitry.
If the problem is in number 2, then there is a moderately good chance they can do something about it in software, if they can a) come up with some suitable algorithms, b)if they have enough processing power and capability in the phone. I suspect they're employing some DSPs in the hardware design integrated onto a chip, so they probably can implement some noise reduction techniques.