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Thread: iPhone 3GS Cellular Signal Fluctuation After purplera1n + ultrasn0w? Restore ≠ useful

  1. #1
    Question iPhone 3GS Cellular Signal Fluctuation After purplera1n + ultrasn0w? Restore ≠ useful
    Hey guys,

    Here's a little bit of background information:
    I have a 32GB 3GS, running OS 3.0 7a341g, my carrier is Rogers Wireless.

    I'm trying to figure out an issue I've noticed ever since I ran purplesn0w (RC2, July 4th) on my 3GS.

    The Jailbreaking process via purplesn0w ran flawlessly. I did not encounter a single issue. I was running VMWare + WinXP SP3 32bit. The program did its thing, and I ran Freeze.app, got Cydia running all within 10 minutes.

    I also managed to download ultrasn0w (version 0.6?).

    However after all that success, it all went weird:

    One particular issue is the random fluctuation of my 3GS' cellular connection.

    Let's say I'm in my bedroom, and my iPhone is to the right of me (right side of my room is a huge window). I accidentally bumped my iPhone to the right (just a few CMs, not even an Inch). That would cause a signal drop to 1 from 5, then it would go back up to 5 though SLOWLY (would take a good 2 minute time). As far as I can remember, my 3GS would NOT have this issue prior to Jailbreaking it.

    I've also been receiving signals to spots that are previously impenetrable by any sorts of radio wave. Example would be the parking lot in the basement.

    So, in short:
    Places I should be receiving constant full strength signal, would get fluctuation, and places where I should not be able to receive signal at all, I would get 1-2 bars. The issues&scenarios I mentioned the above never occur prior to me jailbreaking my 3GS




    What I have done:
    So far, I've tried restoring it. Running the same OS 3.0 7a341g. I was hoping to not encounter the issue again by ridding any traces of "things" that aren't officially created by Apple.

    So, I went for a walk, trying out scenarios again. Similar issue, but a little less noticeable than it was with the 3GS jailbroken.

    I re-restored my phone again, this time, I did a complete DFU restore. Setup my phone as a new phone (not via backup).
    The problem of fluctuating cellular signal is still there.


    My questions:
    Is this something in my head (like it's always been there, I've just started noticing it since the jailbreak, has nothing to do with ultrasn0w or purplera1n) or is it a "real" problem caused by "???".

    Will a DFU restore completely rid ALL traces of purplera1n/ultrasn0w/Cydia?
    I understand if someone were to peer into the NAND forensically, there's likely traces of the phone had been jailbroken in the past, but that's not something the OS should be able to see, correct? Thus a DFU restore should completely wipe everything off, and would not cause any anomaly, since anything remotely connected to purplera1n or ultrasn0w isn't interfering with the vanilla OS?
    Last edited by midnightrockersexpress; 2009-07-06 at 09:52 PM.

  2. #2
    Default Design Flaw!!
    "Signal Fluctuation - Fundamental Design Flaw 3GS"
    by fjafri - 8/22/09 10:49 AM

    I don't if this applies to the 3G model as well but I have discovered what appears to be a very fundamental design flaw. Ever since I bought the 3GS I noticed that the signal strength fluctuated, frequently fluctuating between a full 5 bars and a 1 bar or nothing. I tried to find the answer to this problem on various forums with some weird explanations like attaching a USB cable or a scotch tape to the sim. Nothing I tried improved this. I noticed that it seems to drop just when you made a call and recovered immediately after the call.

    This made me wonder if it had anything to do with how the phone was being held. Some users were saying that two identical units would report different signal strengths at the same location in the same network.

    Anyway after a lot of experimenting I discovered that the iPhone 3GS appears to be extremely sensitive to being held on the lower 1/3rd part of the handset. Holding the phone in the top half recovers a full signal within a few seconds (15/20 secs)!!!!

    You can try this yourself. Putting the phone down on the table or picking it ensuring the bottom half remains uncovered seems to work. Covering the bottom half starts to drop the signal.

    The design flaw is that the receiving antenna should be placed at the top of the phone which is least likely to be covered when held. Either way it's a flaw that Apple should recognize and fix. Other handhelds don't seem to suffer from this characteristic.

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