Since installing OpeniBoot is not yet possible under Windows, a virtual machine running a Linux can accomplish this (but a PC running Linux is highly recommended).
VirtualBox is an x86 virtualization software package developed by Sun Microsystems. It is mainly used by many Windows users to install OpeniBoot because of the fact it's freeware.
However, there's a really annoying USB device conflict between Windows and VirtualBox that prevents users from installing OpeniBoot. It involves error messages about device busy or not available.
This guide will then teach users how to enable USB for VirtualBox under a Windows host. This is only a supplement to the Installing iDroid (Linux) guide. Please refer to that guide.
Before we begin, VirtualBox and Windows can be very temperamental at times. Sometimes, the USB device is checked and loaded in Linux but it still won't be recognized. No matter how many times you reboot Linux in VirtualBox, it will still be the same. The best course is to reboot Windows then reboot Linux. If that still doesn't work, please feel free to ask for help in the Forums or in the IRC channel.
1. It is best to restart/reboot Windows before you attempt all these. Also Linux should have been installed in VirtualBox; and loadibec, openiboot.img3, and oibc have been downloaded in Linux.
2. Once Windows has rebooted/restarted, open Task Manager (right-click the Taskbar or Ctrl+Alt+Del) and end process iTunesHelper.exe. This will prevent iTunes from opening when iPhone is connected in Recovery Mode.
3. Put iPhone in Recovery Mode and connect via USB. The easiest way to enter Recovery Mode is to turn off the iPhone, wait a few seconds, hold the Home button (the button with the White square) and connect iPhone via USB. Keep holding the Home button until the Recovery screen shows up (the default is iTunes icon with the USB wire).
4. Open VirtualBox. iPhone should still be connected in Recovery Mode.
5. Click/Highlight the Linux distro you are using (example Ubuntu), then click the Settings button beside New and Start.
6. Navigate to the USB tab on the Right. Make sure "Enable USB Controller" and "Enable USB 2.0 (EHCI) Controller" are checked.
7. Click the Add button (the button with the USB icon with the +).
8. If your iPhone is still in Recovery Mode, it should appear in the list of USB devices as Apple Inc. Apple Mobile Device (Recovery Mode).
10. Click the OK button to save the Settings.
Booting Ubuntu and OpeniBoot
11. Start/boot your Linux distro. iPhone should still be in Recovery Mode.
12. Like in the tutorial, open Terminal then go to the directory where loadibec and openiboot.img3 are located. Load OpeniBoot with the command:
sudo ./loadibec openiboot.img3
13. From Recovery Mode, iPhone will now display the OpeniBoot menu. Using the Power/Volume Buttons, select Console (the middle option) and press the Home button to execute.
14. You should now be in the OpeniBoot Console.
15. Exit Terminal and shutdown Linux.
OpeniBoot Console Mode
16. Return to the Settings for your Linux distro. Navigate again to the USB tab in Settings.
17. Add another USB device. Your iPhone should still be in OpeniBoot console. Add Apple Inc. Apple Mobile Device (OpeniBoot Mode).
18. It should now appear in the list of USB Device Filters, make sure it is checked.
19. Press OK and reboot/restart Linux in VirtualBox.
20. Proceed with iDroid installation with Terminal command:
Or refer to the Installing iDroid (Linux) guide for more information.