Knox Configure (KC)
When setting a custom booting animation in Knox Configure (KC), the booting animation and sound file are unsynchronized. The animation begins before the sound file.
There is a flag in the device framework that is disabled by default on consumer devices, causing the asynchronous boot animation.
This is expected behaviour in the default system boot-up logic, and cannot be changed.
You can manually synchronize the animation and sound files by adding blank images in the frames before the custom images, imitating the black screen shown during the startup process. The blank images delay the animation so it begins with the sound file.
For steps on how to create a custom booting animation, see the KC admin guide.