As per my original link....
As a Dashboard
XBMC can be run as the default dashboard of the Xbox. That means that it is the first application that gets loaded when you turn on the Xbox. With an FTP Server, XBE launch function, and easy to use design, not to mention its unparalleled ability as a media center, XBMC is a great option as a dash. There are at least three different ways to install XBMC as a dashboard.
Option 1 - Using the Team XBMC Shortcut.xbe (Recommended)
Team XBMC recently developed their own Shortcut tool. It comes in 2 “flavors”:
OpenXDK (source and pre-compiled binary available in SVN)
MS XDK (only source available in SVN)
Download link to pre-compiled OpenXDK: Shortcut XBE.
As a precaution you should have a bootable rescue disc with a ftp enabled dashboard on it at hand if anything goes wrong (See below).
Both versions work in the same manner:
Find out the filename of your current dashboard (i.e C:\evoxdash.xbe for the Evox dashboard): That is the dashboard your Xbox is booting. (this will usually be either "c:\evoxdash.xbe", "e:\dash\default.xbe" or "e:\dashboard\default.xbe". Softmod users should note that "c:\xboxdash.xbe" is very likely the boot trigger for their softmod, as is NOT to be messed with).
Rename your current dashboard to an alternate bootable name. This will be used as a fallback if execution of the new shortcut fails (depending on your mod - most softmods will not fallback in this way. If using a softmod, make sure you've got your EEPROM data backed up before messing with the system boot files). Consult the table below, or www.xbox-scene.com for details on your dash.
Download the XBMC Shortcut XBE from the link above and rename it to whatever the dash was named (usually evoxdash.xbe)
Upload the renamed Shortcut XBE (i.e. evoxdash.xbe) to where the old dash was (Usually the root of the C: drive). The Shortcut XBE is now effectively your dashboard(!)
Install XBMC as a regular application to somewhere on E: or F: (for example, E:\Apps\XBMC) (Instructions on how to install XBMC can be found under Installing XBMC as an Application)
Create a text file on your computer with the same name as your renamed Shortcut XBE, except with the extension .cfg instead of .xbe (i.e. evoxdash.cfg) and put the path to the installed XBMC\default.xbe inside it (eg. E:\Apps\XBMC\default.xbe)
Upload the text file you just created to the same place you uploaded ShortcutXBE to in step 4. You should now have two files in your boot dash location. If your previous dashboard was Evox, These files will be named evoxdash.xbe and evoxdash.cfg. The .xbe is the shortcut XBE you just uploaded, the .cfg is the text file containing a path to XBMCs default.xbe
Congratulations, now you are all set and don't need to alter the shortcut again, unless you change location of XBMC's default.xbe.
Please note that step 2 is optional. The actual fallback order is BIOS dependant. If you don't know what BIOS you are running, you're at risk. First try the xbe given by the .cfg file. Otherwise, the following filenames can be tried. But, the safest backup is to create a bootable rescue disc with a ftp enabled dashboard on it. See xbox-scene.com for details.