My Host OS is Ubuntu 10.10 and guest OS is WinXP on the VirtualBox version downloaded from Oracle including "VirtualBox 4.0 Oracle VM VirtualBox Extension Pack" so that USB passthrough works. This works in general (I was able to back up my iPhone to iTunes in the guest OS), but some devices aren't available even though they're ptrovided in the VirtualBox settings.


  • In the VirtualBox settings for the guest OS, there's the part where you can select which of your USB devices should be visible to the guest OS. I've selected several devices including the iPhone. So far so good.
  • Then an iOS upgrade came along; my iPhone is now in DFU mode (or recovery mode?) and represents itself not as "iPhone" but as "iPhone (DFU mode)".
  • I have now also added this device to the list of USB devices that the guest OS should see -- but it doesn't see this device. The DFU device is listed in the menu of USB devices available to the guest OS, but it's disabled (greyed out)! So I can't select it, so the guest OS doesn't see it.


  1. Am I right in expecting that the guest OS ought to see the DFU device when I add it in the VirtualBox settings?
  2. What steps do I need to take so that the guest OS will really see the DFU device? Why is the DFU device greyed out, and how do I make it selectable?
  • I have the same problem here. I tried everything. Any solutions? – fscosta Jul 12 '11 at 15:10

Disclaimer: I don't own an iphone, and have no way to test any part of this answer. So it is all theoretical knowledge, quite possible wrong.

DFU is a standard way of updating device firmware. The device will appear as a DFU device to the host, the host will upload a firmware update to it, it will apply the update and appear as a new device to the host. So what it's likely happening is that VirtualBox is not seeing the new device, not the DFU one.

This are the steps that I would take to resolve/debug the problem:

  • Go to VirtuabBox configuration, in the USB section delete everything. This will allow VirtuaBox to catch all the USB devices. See the screenshot.

enter image description here

  • Start VirtualBox, connect the device. It should appear on the Devices->USB Devices Menu as a DFU device. Click on it. Now the guest OS will install it's drivers and upload the firmware to it. Wait patiently.

enter image description here

  • Go again to the Devices->USB Devices menu. It should be there as a different device. Click on it. Enjoy.

Sorry for the screenshots language, if you don' understand then just ask. The devices are disabled on the second screenshot because VirtualBox is running under an user not member of the virtualbox group.

  • Screenshots always help, don't worry! And your steps is exactly the process I expected. But I already did this and the odd thing is that the submenu for USB devices does show the DFU device but it's greyed out --> so I can't select it --> so the guest OS can't see it --> so no drivers are installed for it --> so the phone stays in DFU mode. – Torben Gundtofte-Bruun Feb 9 '11 at 9:41
  • I added this clarification in my question - see italic text. – Torben Gundtofte-Bruun Feb 9 '11 at 9:45
  • The usual reason why usb devices are greyed is because you are not member of the vboxusers group. If all the usb devices are greyed this is the likely cause. If not, then try to run VirtualBox with sudo to rule out permission problems. – Javier Rivera Feb 9 '11 at 11:28
  • My user was in the vboxusers group and I still see grayed out deviced - the thumb drive from which I booted Lubuntu, and a SATA SDD connected via a USB adapter. Extremely frustrating to not be able to access the SDD. Of course, the host Lubuntu can access it just fine. – Dan Dascalescu Dec 31 '12 at 9:06
  • Have you installed both the extension pack and host additions?. VB can't only access a USB file-system when it is not used by the host. You can't have your SSD mounted both in the host and guest system. – Javier Rivera Dec 31 '12 at 11:49

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