I have a Droid Razr, rooted, .215 leak.
I read the post on extracting the Bootanimation.zip file and modifying the desc.txt file. I went in and looked at the desc.txt file and everything was already there just like you guys said it should be. I followed the logical course and looked in the Mobility folder and the droidhd.ogg file wasn't there. I copied it over from the /system/media folder and rebooted. When I rebooted I had the boot sound back. I didn't have to change permissions on anything.
Don't really know exactly why this worked but it did. Just thought you guys would like to know.