Tuxuser released a new homebrew application that will allow you to easily update just the XeLL part of your freeBOOT NAND:
[QUOTE]
XeLL Updater for freeBOOT - v1
Based on dashlaunch installer by cOz
!!!!!!!!!!!!!!!! USE AT YOUR OWN RISK !!!!!!!!!!!!!!!!
Use it on Single NAND-freeBOOT only (9199, 12611, 12625 or above - if nothing on the flash layout changes!).
Rename xell-2f.bin to updxell.bin and stuff it together with the default.xex on your xbox.
Execute the XEX, Confirm the update.
Shutdown your XBOX, press eject to poweron and you will be greeted with an updated XeLL :P
Greetz to cOz, Cancerous, Redline99, GliGli and Ced2911