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On OS X, I can charge my iPhone without any problems, but Windows always complains about not having enough power, regardless of what USB device I connect to the keyboard. Why is that? How can I enable Windows to overcome the limitations of the Apple keyboard?

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It is likely a problem of Apple not using standard driver models for USB in the keyboard, thus the keyboard can not ask for the power needed to charge an extra device. Blame Apple for always having to be proprietary, not MS for sticking to USB specifications. en.wikipedia.org/wiki/Universal_Serial_Bus –  AthomSfere Jul 13 '13 at 17:37

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As @AthomSfere pointed out in his comment, this is more a matter of Apple doing something weird (not properly reporting device capabilities) rather than Windows doing something wrong.

Regardless, this is fixable by hacking the Windows registry and forcing a higher amperage to be reported for the USB hub in the Apple keyboard.

Not-so-complete actions to take:

You have to find the "Generic USB Hub" that represents the keyboard's hub in the Device Manager, determine it's Location Information (Details tab of properties), then search for it in the registry. You want to find it somewhere in the HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\USB key (unfortunately it may show up a couple or more times, so you have to do a little trial and error).

Once you determine which device key represents that hub, take ownership of its key, then give permission to yourself or Everyone to change it.

Then add a ForcePortPower DWORD (32-bit) value in the "Device Parameters" subfolder, and give set it's data to "500" (decimal).

Unplug the keyboard and plug it back in and wait for it to be re-detected (or reboot).

Once it's done, if all worked right you should be able to go back to it's properties in the Device Manager and under its Power tab it should now report "This hub is self-powered" with a Total Power of 500mAh and Windows should stop complaining about the lack of power when you plug in a device.

YouTube video tutorial covering how to do this step-by-step: Apple Keyboard Hack - Fully-powered USB ports on a PC!

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I did that, but nothing's changed. Windows still complains about missing power when I connect something that would work on OS X, even after a reboot. I double-checked that I got the right device in the device manager, and I'm pretty sure that I did. I'm using Windows 8, is that something that could've been important? –  Peter W. Jul 15 '13 at 16:53

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