To remove the boot sound....
from your run box on PC,
cmd
cd\
cd sdk\tools
adb reboot recovery
phone reboots to clockwork recovery
on the phone:
mounts and storage, optical mouse click
mount /data optical mouse click
mount /system optical mouse click
back at your computer
type:
adb shell
when you get the #
cd /system/media
mv android_audio.mp3 android_audio.bak
type:
exit
unmount,
reboot
no sound on reboot...
and to get it back....
same steps as above, except its :
mv android_audio.bak android_audio.mp3
and voila... ITS ALIVE.... ALIVE!!!