It's been a while since I had to mess with mine.
Does it boot up to a screen at all now?
If I remember right you should be able to boot to a screen where it gives you the choice of where to boot from, ROM, RAM, HD? I'm pretty sure mine boots from the ROM.
I used to really get mine screwed up (software wise) when I first did the CF mod. But mine still works just fine. I doubt you bricked it, unless there is an electrical problem with it.
edit to add:
The Rockbox forums used to be a good place to get questions answered, but I doubt they are very active over there anymore.