tmobile mda updating problem

[crazymac]

hey i have a question, i have a tmobile mda that wont update past wm5 i have tried a whole bunch of diff roms and it still stays at wm5, my old mda worked with every rom until it got stolen now i got another one and i updated it to wm5 and now i cant update it to any other rom the button rom is supposed to wm 2003 and it stays wm5
is there any way someone can give me a good working wm6.5 rom please i need this.