Does the Canon 450d have custom firmware? Doing a quick Google search didn't really find anything. And, along similar lines, is the 450d even capable of flashing its firmware? Or are we basically stuck with the stock firmware the camera comes with?
As far as I'm aware it doesn't, CHDK only runs on the 400D and lower (due to the firmware chipset it ran it was fairly hackable), and Magic Lantern starts on 500D and goes up from there.