Yes, its possible.
You can either soft mod it or hard mod it (modchip)
To softmod you need a memory card that can hook up to a PC via USB (Action Replay has this) or a normal memory card (if you have access to someone else's soft/hard modded xbox that can copy some files onto it for you) & you also need a exploited game like Splinter Cell 1 (1st release, not platnium version), 007 Agent Under Fire, Mech-Assualt.
Then you just download withever game save hack for the game you got (out of those above) Load up the game & load the save & you will be in a hacked dashboard called Evo-X.
Now i dont know how tech savy you are, but you can either stop here & just keep booting up your game of choice & then loading your save to access the hacked dash (& there for you can run your backup) so it acts like a boot disc.
or
You can install the hack from the new dash onto the HDD from within the dash & have a perminit-hack & do other stuff like multimedia & emulators etc.