This tool allows to disable/mute/silent the system sound from /system/media/audio/ui/, such as the poweron sound.
It is as simple as selecting the item(s) and then click on "Nullify". Restoration is available as well should the users want to revert the process.
Use case: power on sound effect, PowerOn.ogg (Different phone manufacturer may use different filename)
Behind the Scenes
How Nullification Works:
(1) Rename the file (become a backup)
(2) Create an empty file with the same name
(3) Grant the same permission
How Restoration Works:
(1) Delete the 0 byte empty file
(2) Rename the backup file
* Requires root access as this app is access /system/
Warning: If the system sound is required by law in your countries, you shouldn't use this tool to disable them.