According to a message posted by one of their forum members, the reception issue could be potentially fixed by merely taking the SIM card out of the tray, re-seating it and then reinserting it.
The iPhone user, who posts under the handle jav6454, writes:
"My iPhone suffered from the same green spot effect as the iPhone from the user on MacRumors. Knowing full well, it was a hardware problem I set up an appointment for today at 6:30 PM…the Genius reswaped the SIM card to my phone back and handed it to me. (My iPhone spent 15 minutes with out SIM card while the Genius did all his tests on my and replacement unit, and while he asked for 2nd opinions on the green blob issue)
I went on my merry way, but realized something now. No matter what position I held my iPhone 4 in, the signal never decreased. I held it the many ways I know the signal issue pops and nothing. No bar loss, no signal loss, no call drop. NOTHING. So there you have it.
I am theorizing that moving the SIM card had something to do with the signal issue, because the only thing I have done to my iPhone 4 differently is take out and reinsert the SIM card. Other than that no other changes to it. No setting change, no software change no nothing. Just reinsertion of the SIM card."
Surprisingly, quite a few users have responded claiming to have seen significant improvement in signal reception by using this fix. However, it also needs to be noted that an equal number of users do not seem to have observed any change.
According to one of the members, the root cause for the reception issue may lie with the way the SIM Card is aligned on the SIM tray. He writes:
"The metal part of the sim card is not centered and is contacting the sim tray. The sim tray is steel and the sim tray is contacting the outer antenna band. Once you touch the phone, this could be causing a sim issue. If when you touch the antenna line on the lower left it changes the state of frequency, power or what ever, it might actually be messing with the sim card. The metal on the sim is connected to the sim tray, the sim tray is connected to the antenae and the antenae is connected to your hand when you touch the phone. Take a look at your sim card and see if the metal is just off center enough to touch the tray."
MacRumors points out that users who tried to isolate the SIM from the tray with the help of an electrical tape or by cutting the SIM on the opposite side have reported mixed results. Considering that nearly half of the users who have tested this fix did not notice any change, we may have to stay skeptical for the moment.
However, we will be interested to see if this fix works for our readers as we don't see any harm in trying it out. Do try this on your iPhone 4 and let us know if you notice any significant improvement in signal reception.
[via MacRumors Forums]