Simply download the Fall 09 update from Microsoft
Extract $SystemUpdate to a USB stick, and then put it in your 360
As soon as you put the USB stick into the 360, it will prompt you to update. Choose “Yes, update now”
It will see that you are already on 8955, and install ONLY the avatar stuff on the hdd.
As long as you have the R6T3 resistor removed, there is no risk of burning an efuse, and rendering your console un-hackable. (Users have installed this update with out removing R6T3, and every thing is fine, as XBReboot has virtual efuses) As with everything here, DO SO AT YOUR OWN RISK 😉
If you have since updated to freeBOOT 0.032 (if you haven’t, you should) then you will now be running dash version 9199, in which case you will need the full 9199 update in order to install the Avatars.