Can jailbreaking be the cause of bad bluetooth quality?

Discussion in 'Jailbreaks and iOS Hacks' started by Vandam500, May 4, 2009.

  1. Vandam500 macrumors 68000


    Sep 29, 2008
    Is it possible that having my iPhone jailbroken with:

    -iNav Theme

    Causes the iPhone to have too little memory for my bluetooth headset? (Plantronics 925), causing people to barely hear/understand what I say. I have tried with Full 3G and Edge signals and they say the voice goes in and out. I know its not the bluetooth because have tried it with other phones and its great.

    Any thoughts?
  2. bruinsrme macrumors 603


    Oct 26, 2008
    Do you know if the BT was working OK prior to jailbreaking?
  3. ppc750fx macrumors 65816

    Aug 20, 2008
    No. Next question.
  4. Vandam500 thread starter macrumors 68000


    Sep 29, 2008
    I have never tried it prior to jailbreaking.

    Any evidence to back that up? I mean doesn't bluetooth use memory as well or not? We all know the iPhone has little ram and jailbreaking it causes it to have even less ram available. So it's not possible that low memory can be the cause of bad communication on the bluetooth?
  5. ppc750fx macrumors 65816

    Aug 20, 2008

    1) Jailbreaking doesn't cause a reduction in free RAM.

    2) Assuming that a reduction of free RAM were the issue, I can only think of one reason why memory starvation would cause a reduction in quality but not a loss of functionality: if the RAM were exhausted to the point where the kernel needed to page out to disk.

    3) Paging would only cause issues with Bluetooth quality if the BT drivers/systems used dynamic allocation which, if they're in kernel mode, seems slightly unlikely. If you're writing code that powers a hardware feature you often just malloc/mmap a big block during initialization and use that.

    4) Dynamic allocation in the BT drivers/code wouldn't explain it though, because there's no paging latency. Why? Because the iPhone's OS doesn't page to disk. Since there's (essentially) no paging overhead, memory starvation would only cause the OS to free inactive/read-only pages (code pages). That might affect the performance of other stuff, but it wouldn't affect the app making the allocation request -- that would be massively counter-productive.

    So no, I doubt that it's the process of jailbreaking that's caused your issues.

    The simplest explanation is a bad battery in your BT device. The next simplest is a wonky BT chip. After that I'd wonder about whether you might have installed something that screws with the BT stack; I don't recall whether any unofficial apps do, but it's certainly possible.
  6. Vandam500 thread starter macrumors 68000


    Sep 29, 2008
    That's a really detailed explanation :eek: Thanks! But it's not the BT battery, it's been charged several times and is on full battery. Still investigating the issue.
  7. ppc750fx macrumors 65816

    Aug 20, 2008
    Then (unless you've been mucking about with your drivers or BT stack) my bet is that it's either a poor connection to one of the devices or a faulty BT chip.
  8. jarjarblinks macrumors 6502


    Nov 15, 2008
    From a simplistic POV, jailbreaking does not entail changing the hardware in any aspect, you're only modifying the software that the OS runs on.

    Perhaps you can try to see if the poor BT connection only happens at any particular spot where you may have signal interferrence or there are other devices that interrupt with the iPhone?

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