Already modded Xbox needs upgrade

ok if you want the life story just ask me to add any details you think is important to this discussion..ok so I have an xbox it has been modded since Boxing day 2008 and now with wave 3 games it cant play them...i just want to know 2 things...1.does not knowing whether my xbox is on 1.4 or 1.5 affect me at this point(do i need to take different steps? for either) and I've seen many methods and most if not all reflect back to specific drive types what i want to know is do I need to know anything about drives(i wasnt the one who modded it and the shop is very elusive on sharing details) and 2.how can i find out what appropriate method to use not knowing the history of my xbox

-playing with a monkey wrench