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Make an iPhone work on a 20" iMac G4 iOS devices
The system requirements for the iPhone state that it requires a computer with a USB 2.0 port. In actuality, however, I had observed that iTunes would sync with an iPhone on a iMac G4 with only a USB 1.0 port. Hence, I was surprised when iTunes running on a 20" iMac G4 computers could not see the iPhone, but iPhoto could. Because calling Apple Support was not an option (iPhone requires USB 2.0 ports), I attempted to solve the problem myself.

The 20" iMac G4 has three USB 1.0 ports. Surprisingly, the System Profiler indicated that the iPhone was attached to a fourth, phantom USB 2.0 port. This did not seem correct, as other iMac G4 computers showed the iPhone connecting to one of the three physical USB 1.0 ports.

I decided to remove the phantom USB 2.0 port. Be warned that the following procedure, while working on my system, may, if followed, prevent your system from restarting or impair its operation in some horrible manner. If you decide to remove a phantom USB 2.0 port, proceed at your own risk after being sure you have a current backup of your system.

I noted that the System Profiler said the port was attached to the Host Controller Driver AppleUSBEHCI. Knowing that the other iMacs G4s showed the iPhone connecting via the Host Controller Driver AppleUSBOHCI, I decided to remove the USB 2.0 driver and see if the iPhone would connect via the proper driver.

First I logged in as Root. The USB 2.0 driver, AppleUSBEHCI.kext, is located in the package System » Library » Extensions » IOUSBFamily.kext. I selected IOUSBFamily.kext and used Show Package Contents to view the contents of the package. I opened Contents » PlugIns, and located the driver file, AppleUSBEHCI.kext.

I dragged this file to the desktop and rebooted my computer. Opening the System Profiler, I verified that the iPhone was now attached correctly to one of the iMac's USB 1.0 ports. At this point, iTunes still did not recognize my iPhone, so I downloaded the current version of iTunes and reinstalled it.

I am not sure why this step was needed, but I suspect that reinstallation forced iTunes to remap itself to the correct USB ports on my computer. When the installation completed, I plugged in the iPhone and it was recognized by iTunes.

[robg adds: Definitely in the "proceed at your own risk!" category. Note that you could also use Terminal and sudo to get this done, skipping the root login.]
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Make an iPhone work on a 20" iMac G4
Authored by: patgmac on Jul 23, '07 08:38:27AM
Umm...The 20" G4 iMac has USB 2.0 ports and as far is I remember, there was only 1 20" G4 iMac.

If I remember correctly, the internal modem was on a USB bus and was USB 1.1 and was shared with one of the external USB ports which cause that one port to be USB 1.1.

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Make an iPhone work on a 20" iMac G4
Authored by: jdownward on Jul 23, '07 10:57:01AM

In addition to the 20" iMac my wife has at work, at home, we also own a 20" iMac. After upgrading it to 10.4.10 with all the patches installed, iTunes would not recognize her iPhone even though the Apple Profiler showed it was connected to a phantom USB 2.0 port. Again 4 ports were displayed by the System Profiler, but only 3 ports were in the back of the iMac. Proceeding as before, I removed the 2.0 USB driver, reinstalled iTunes, and her iPhone was immediately recognized by iTunes.

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The "phantom" probably isn't the one you think
Authored by: VRic on Jul 23, '07 03:39:58PM

I suppose the USB 2.0 port showing your iPhone really is one of the 3 external ports, and the "phantom" one (internal) actually is one of the others in the list, probably USB 1.1 if the internal modem is present.

Given there's only 2 USB 2.0 controllers shared among the 4 ports (3 external and 1 internal), it may be possible that all appear as USB 1.1 if the internal modem is present and something USB 1.1 like a keyboard is attached to the other controller.

Maybe your problem and solution have more to do with some glitch between USB 1.1 and 2.0 peripherals trying to grab the controller and only succeeding when the only USB 2.0 peripheral reverts itself to USB 1.1 after you killed the USB 2.0 mode on the host.

If you have other USB 1.1 peripherals (keyboard, old USB hub, etc.), try plugging them to another port to free one of the 2 controllers for USB 2.0.

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The 20" iMac G4 DOES have USB 2.0
Authored by: VRic on Jul 23, '07 03:19:46PM

As patgmac wrote earlier, this iMac model has USB 2.0. And to be exhaustive, all 3 sizes of the last version of the iMac G4 do (those are the september 2003 15" 1.0GHz, 17" 1.25 GHz and 20" 1.25 GHz).

Or in other words, all the > 1GHz iMac G4s have USB 2.0, except the earlier 1.0 GHz 17" (the sept 2003 17" being 1.25 GHz, not 1.0GHz).

Now you know which eBay auction to pick :-)

As for the "phantom" port and occasional USB 1.1 mode, I'm not sure but the internal USB modem port hypothesis sounds mighty convincing. I can't check right now, but I'd expect to find either a 4th USB port with the internal modem on it, or no modem but still a 4th empty USB port.

What I'd like to know if someone has one to test, is if the ports appear as USB1 or 2, or only some of them, or if it depends on the peripherals connected to them, etc.

If as suggested one of the external ports is gagged to USB 1.1 speed by the internal modem, I'd like to know which one it is to plug any USB 1 peripheral and the keyboard there, instead of wasting the others' potential. And if it is the modem causing USB 1 mode, maybe the absence or removal of the modem would revert all 3 external ports to USB 2.

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The 20" iMac G4 DOES have USB 2.0
Authored by: jdownward on Jul 23, '07 04:19:37PM

To clarify, non-synching is not related to which USB port the iPhone is plugged in to (two iPhones have been tried). As the iPhone USB connecter is moved from physical port to physical USB port on the iMac, the location of the phantom 4th USB 2.0 port in the System Profiler listing moves around and while the iPhone is seen by the System Profiler as a 2.0 device attached to the phantom 4th (non physical port) USB 2.0 port, the presence of the iPhone is not seen by iTunes.

The combination of removing the 2.0 USB driver and reinstalling iTunes appears to enable the iPhone to Synch with the iMac G4. It correctly appears on a physical port whose location switches as the USB connnector is placed into different USB connectors on the back of the iMac. Perhaps just reinstalling iTunes would do that by itself.

However, I do know that a fresh install of 10.4.10 and iTunes 7.3.1 by itself will not enable iTunes to see the iPhone on either of the 20" iMac G4s (purchased 6 months apart) that we use at home or at work. If this iMac model indeed has a USB 2.0 port, on at least these iMacs, the port does not allow iPhones to sync with iTunes. A sample space of 2 certainly, however, does not rule out the possibility that iTunes 7.3.1 running on other OS X 10.4.10 20" iMac G4s will synch perfectly with every iPhone they see. Just not ours.

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Make an iPhone work on a 20" iMac G4
Authored by: jdownward on Jul 24, '07 06:44:13AM

Using the System Profiler, with mouse plugged into keyboard and keyboard plugged into any one of the three physical USB ports, the two empty ports appear to be USB 1.1 ports. It does not matter which of the three ports the keyboard is plugged into.

Attaching the iPhone to either of the two empty ports leaves those ports alone and the Phantom USB 2.0 port appears in the list of USB ports. Moving around which port the keyboard/mouse plugs into, has no effect on this behavior, and while iPhoto will see the iPhone on phantom USB 2.0 port (which ever physical port it is plugged into).

I have been unable to get the iPhone to be recognized by iTunes when it sits on this Phantom port (regardless of which physical port it is plugged into). On the other hand, our iPhones are always found when they connect to a physical USB port that reports itself (prior to iPhone being plugged in) as being either USB 1.1 or USB 2.0.

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