Hello! I recently took out my good old EX475 from forever ago. I got it new in Christmas of 2008, and I mainly remember running Linux on it, but I do remember toying a bit with WHS v1. Well anyway, I was recently wanting to revert it to stock, and I realized my SMI flash was messed up! Great. And every link here is dead!
Well good news for all, I found my backup and I found another source too!! Why don't you grab a copy of this?
My backup | My Internet Archive upload | Another person's EX47x SMI backup
I can confirm mine works - I hope this does help someone!