And then:
- Flash bootsound_disable-signed.zip for disable
- Flash bootsound_enable-signed.zip for enable
This way is more easy for all people
mount /system
mv /system/customize/resource/android_audio.mp3 /system/customize/resource/android_audio.mp3.nothanks
mv /system/media/android_audio.mp3 /system/media/android_audio.mp3.nothanks