Good news !
21028 and 21040 both boot for me just fine on my Sprint Touch Diamond.
Not exactly sure what I was doing wrong before, but no problems whatsoever when I went through the process again, today. I deleted all of the files and started over and it worked great.
So, when do you teach how to build our own base ?
Best regards,
-boggsie
Interesting development - I can't find a version of MS Voice Command that will announce incoming calls via bluetooth (jawbone) on a post-21000 rom base.