How to Install Raspbmc to USB Manually from Windows: A Windows Raspbmc Installer does exist that enables a user to install and run Raspbmc from a USB drive on their Raspberry Pi. However, if your running a different version of .Net than 3.0 (even a newer version), the RASPBMC installer will crash with an error stating "raspbmc installer has stopped working".
Have no fear, you can easily duplicate the process of the Raspbmc Installer by following the simple steps outlined below:
Installing Raspbmc to USB Manually:
Program and File Prerequisites:
Download and Install 7-Zip (to be used for extracting the img.gz file)
Download and extract Win32 Disk Imager (To be used to put the img file on the SD Card)
Download or create a blank file named USB (make sure to save file as USB – not USB.txt)
Preparing the SD Card and USB Drive:
Format both your SD Card and USB drive as Fat32
Extract the installer.img file from installer.img.gz using 7-Zip
Using Win32 Disk Imager Win32DiskImager.exe, (1.) Browse to and select your installer.img file, (2.)Under Device, select the drive letter of your SD Card, (3.) Click Write
Once Win32 Disk Imager has finished, copy the blank USB file to the SD Card.
Plug the SD Card, USB drive, and an Internet adapter into your Raspberry Pi and let it boot up.
If all goes well, Raspbmc should begin to boot from the SD card, connect to the server, and then state that it has detected a USB drive connected, and that it is going to install to the USB, unless you remove the USB and power off within 60 seconds.