Huawei made the /system partition into a erofs filesystem which is readonly. This complicates alot of things since we cannot simply unlock the bootloader and change build.props for VoLTE.
The pixel-volte-patch does not work since it uses api level 29 (aka Android 10). Unfortunately the Honor play only got updates to Android 9.1 which only has api level 28.
This is important because api level 29 added in a hidden api to override the carrier config.
If we had Android 10 we can access this api by installing shizuku which gives apps the ability to run as shell.
shell is granted to apps by extending the adb shell session.
The Magisk module volte-wifi-calling-enabler does not work since it tries to modify build.props directly. Unfortunately /system is behind a read only filesystem.
It also might not be working since it doesn’t set ro.config.hw_volte_dyn to false (Manually setting this through MagiskHidePropsConf gets VoLTE toggle to show up on my phone).