The modified plist files in attached with this article can raise your iPhone’s volumes
First, get these plist files:
Extract the downloaded files, and put the plist into appropriate folders on iPhone:
com.apple.celestial.plist in /var/root/Library/Preferences/ SystemSoundMaximumVolume.plist in /System/Library/Frameworks/Celestial.framework/
Restart the phone to apply the changes.
