

Restoring your iPhone 3G to OS 3.1.3 - obelix

I had installed iOS4 on my iPhone 3G and saw it crawl to becoming an iPaperWeight.  It was horribly slow in launching every app and the keyboard was so slow it was unusable.<p>I had to restore it back to 3.1.3.<p>spicyj gave me the starting point here:<p>http://news.ycombinator.com/item?id=1453553<p>I ran into a few problems, here is how I got it to work:<p>1)  Download 3.1.3 firmware for iPhone 3G from http://www.felixbruns.de/iPod/firmware/.<p>2)  You have to put your phone in the appropriate DFU mode for downgrades.  (Whatever DFU stands for).<p>Switch of your iPhone, connect the USB cable to your mac / PC and put it in DFU mode with following instructions - Click the Home + Power On button for 10 seconds exactly - Release the power button and continue to click on Home.  The display should never turn on, but your iTunes should recognize the phone and warn you about recovery mode.<p>3)  Option click the restore button and choose the 3.1.3 firmware you downloaded.  Let it perform the recovery.<p>4)  If it fails with an error 1015, click ok.  The firmware is restored, but you have to snap the phone out of the recovery mode now.<p>5)  Download iRecovery as explained in this link.<p>http://www.ihackintosh.com/2009/09/recover-iphone-3gs-from-apple-logo-or-recovery-mode-loop/<p>6)  As explained there, copy the libusb-0.1.4.dylib to /usr/local/lib and give it executable permissions.<p>7)  Run ./iRecovery -s from the extracted directory.<p>8)  Set autoboot to true inside the iRecovery console:<p>setenv auto-boot<p>saveenvs<p>fsboot<p>9)  I had to do fsboot thrice and nothing happened.  It should have rebooted by now.<p>I did a power down and restarted the iPhone, and it was back up on 3.1.3 firmware.<p>If you run into problems or your phone is stuck in the recovery icon mode (USB port meets iTunes icon), please check out iRecovery and read all the possibilities there (there is a reboot command which might work, I didn't try it).<p>The downside to this is since my last iPhone backup was with iOS4, I could not restore it, I had to setup my phone as new.  That is something I can live with.<p>Upside - the phone seems MUCH faster now ;).
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Aaronontheweb
Is the 3G hardware just not able to handle iOS4?

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gaiusparx
I think its case by case. Some find it faster after the upgrade. I suspect its
cause by some data or apps during the upgrade. Some find it running alright
after doing a clean install. Or maybe its specific to certain batches of
iPhone 3G hardware we will never know. Apple is rumored to release 4.0.1
pretty soon, so hopefully it will solve this slow issue on 3G hardware. iOS
3.x code base is Leopard base. iOS 4 is Snow Leopard. So by right iOS 4 should
run faster if not smoother on same hardware base on Leopard/Snow Leopard
upgrade experience.

Lifehacker has a guide: [http://lifehacker.com/5572003/how-to-downgrade-your-
iphone-3...](http://lifehacker.com/5572003/how-to-downgrade-your-
iphone-3g\[s\]-from-ios-4-to-ios-313)

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pascal_cuoq
"iOS 3.x code base is Leopard base. iOS 4 is Snow Leopard"

Along with other changes, many of which do not affect the iPhone either, the
biggest change in Snow Leopard was to switch all binaries and the default
compilation target from IA-32 to AMD64. You shouldn't expect the Leopard ->
Snow Leopard upgrade experience to translate to ARM-based mobile phones.

PS: I upgraded an iPhone 3G to iOS4, some apps are slower and others even
crash more often, but the home folders and the "Cellular Data" setting in
Settings->General->Network make it up for me.

