Using a old sagem sky router for other ISP'S

Hey. I hope somebody can point me in the right direction what to do (If you need to PM me to discuss please do as I don't want to get into trouble with the mods) Anyway, I have a old sky sagem f@st 204 I think. I'm leaving BT (Nightmare with customer services and expense) Signing up to ADSL24. Just wondering to save a bit of money can the firmware be hacked to work on another ISP?