Are you trying to install MEPIS 8, 7, or earlier? -- In April I had a Dell in my Wednesday Linux Workshop which had a Broadcom (note spelling, this is the way they
spell it on their web site) chip. Sorry, don't ask me which chip -- I don't remember & the owner says:
The computer was a Dell Inspiron 6400. I can't remember which chip it used and have no idea how to find out.
In any case, the chip wasn't working w/ MEPIS 7, & wouldn't work w/ Ubuntu 7.10; but worked OOTB w/ MEPIS 8.
I found this w/ Google Linux