I believe TSR is the same for xbox(terminate and stay, its in the Evo-x settins under Misc) and that would mean when you quit out of the Evo-x dash it stays resident, Stock dash detects this and Says,"Bite my Shiny metal ass"

. You messed with shit you have a right to mess with, We're Micro$oft, Arrrgh!
(That's my guess anyway, dont take this as an expert opinion, I just start the whole Xbox modding a week ago, but i have read a lot of the tuts and FAQs, so i have a good grasp of it)
And are you Turning off your Chip before booting the system? If so that wont work, The MS bios wont start Evo-x, Unless you are running it off a disk, then in that case I'm stumped..
P.S. if you want more proof MS sucks, Open up windows explorer in 2K/XP and Manually type in: "C:\Documents and Settings\Administrator\Local Settings\Temporary Internet Files\Content.IE5" (Where Administrator is your user account if different ) And find a little nicely hidden cache of every thing youve done in internet explorer, regardless of whether you clear your history or not, and while your there hit "up" And try to find it in the parent folder, Good luck...