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12-14-2013, 04:54 PM #1Downgrading from iOS 6.1.3 to 3.1.3
I accidently washed my iphone (3GS 16gb) and now according to the console (using iphone configuration program) it's giving me the battery has "stale" temperature error indicating it is not able to read the temperature of my battery anymore. This causes my iphone to not boot to the lock screen (to prevent a melt-down according my research on the internet) but instead shut-down and boot up again infinitely. What I also found out is that this battery temp check only occures in iOS 4 or higher and downgrading it to 3 will make it boot up again normally. Also the screen and everything works perfectly (even though it has a crack running across it and there is what it seems a waxy substance beneath it). The battery seems to be intact as well.
My questions is how to downgrade it because it does not allow me to do so (apple signs their firmware or something). Anyone who knows how to do this?
12-14-2013, 09:19 PM #2
The quick but not terribly helpful answer: unless you have the necessary SHSH blobs (the signing mechanism) for your particular 3GS for iOS 3.1.3, you will not be able to downgrade*. Apple's the only source of these blobs--either you have to get them direct (impossible at this point, as Apple only signs the most current version of iOS, with a few odd exceptions), or Cydia cached them on your behalf when Apple was signing them. If you were jailbroken or had used TinyUmbrella before June 2010, then you might have them cached.
The asterisk: if you have an old bootrom device (serial number starts **920 - **945, and not all devices in that range are old bootrom), you can use a program like sn0wbreeze to make a custom IPSW that can be restored without SHSH blobs. Also, it's theoretically possible that with a new bootrom device you could downgrade to iOS 3.1.3, but the device will be extremely unstable, as well as a tethered jailbreak.
The hardware question: You totally submerged (and, ostensibly, agitated violently) your iPhone for a sustained period. The device doesn't record a battery temperature, and so won't boot. You say the battery is fine (my gut isn't sure that assessment is entirely correct)? If the battery is in fact fine, could the logic board be gone? Also that waxy substance under the LCD (I am assuming it's under the LCD as well as the front panel glass)... perhaps detergent of some sort?
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12-15-2013, 04:21 AM #3
Thank you for answering in such a short time.
I do not have unfortunately the blob files since the phone is quite old and the computer to which i connected it for the first time doesn't exist anymore. The serial of my device starts with a 829 so I suppose that would not work either (unless it is actually, what you say, an old bootrom device. I'm open for every possibilty to recover my iPhone, even if it ends up to be unstable).
Regarding your hardware questions: the washing machine ran for 1 hour at 1800 rpm and 60 degrees celcius (fabric softener and washing powder) . Despite this, I can power on the device without connecting a direct feed from a charger. Your other guess, that the logic board has been destroyed, could actually be the reason why it's not booting up past the apple logo anymore. I've read some stories and they somewhat correspond to mine. However I am not 100% sure so here is the consolelog of a run:
12-16-2013, 10:19 PM #4
Well it looks like we could disable the watchdog daemon causing backboardd and SpringBoard (and thus the device) to crash, the logs even tell us how (defaults write com.apple.mobilewatchdog WatchdogEnabled -bool no). The question is, can we get a root shell to run that command in time? Redsn0w MIGHT be able to do it (Extras -> Even More -> Preferences -> Boot Args), but that's rapidly advancing beyond my paygrade. The kernel will accept a "-v" flag for verbose boot for example, but I don't think it'll take a raw command like that.
If you've got a spare battery around, try that... but a device that sat in 60șC water laced with detergent for an hour... that's just a prime recipe for dislodging connectors and getting corrosion on the main logic board (and shorting it).