[OnePlus 3 Questions & Answers] rm5:
I looked at the updater script. maybe its what i've marked in red?

ui_print("Installing ROM ...");
show_progress(0.1, 0);
ui_print(".................................");
ui_print("... ViPER|Audio™ ...");
ui_print("... 2.4.0.1 ...");
ui_print("... OnePlus 3 ...");
ui_print(".................................");
ui_print("Mounting system...");
ui_print("Mounting data...");
ui_print("Mounting vendor...");

package_extract_dir("tmp", "/tmp");
set_perm(0, 0, 0777, "/tmp/busybox");
run_program("/tmp/busybox", "mount", "/system");
run_program("/tmp/busybox", "mount", "/data");
run_program("/tmp/busybox", "mount", "/vendor");

ui_print("Deleting AudioFX ...");
delete("/system/priv-app/AudioFX.apk");
delete("/system/priv-app/AudioFX/AudioFX.apk");
delete_recursive("/system/priv-app/AudioFX");

ui_print("Deleting DSP Manager ...");
delete("/system/app/DSPManager.apk");
delete("/system/app/DSPManager/DSPManager.apk");
delete_recursive("/system/app/DSPManager");

ui_print("Deleting MusicFX ...");
delete("/system/priv-app/MusicFX.apk");
delete("/system/priv-app/MusicFX/MusicFX.apk");
delete_recursive("/system/priv-app/MusicFX");

ui_print("Deleting existing ViPER4Android install...");
delete_recursive("/system/app/As");
delete_recursive("/system/app/AsUI");
delete_recursive("/system/priv-app/As");
delete_recursive("/system/priv-app/AsUI");
delete_recursive("/system/app/Ds");
delete_recursive("/system/app/DsUI");
delete_recursive("/system/priv-app/Ds");
delete_recursive("/system/priv-app/DsUI");
delete_recursive("/system/dolby");
delete_recursive("/system/etc/dolby");
delete("/system/app/ViPER4Android.apk");
delete("/system/priv-app/ViPER4Android.apk");
delete_recursive("/system/priv-app/ViPER4Android");
delete_recursive("/system/app/ViPER4Android");
delete("/system/app/ViPER4AndroidFX-2.4.0.1.apk");
delete("/system/priv-app/ViPER4AndroidFX-2.4.0.1.apk");
delete_recursive("/system/priv-app/ViPER4AndroidFX-2.4.0.1");
delete_recursive("/system/app/ViPER4AndroidFX-2.4.0.1");
delete("/system/app/ViPER4Android FX-2.4.0.1.apk");
delete("/system/priv-app/ViPER4Android FX-2.4.0.1.apk");
delete_recursive("/system/priv-app/ViPER4Android FX-2.4.0.1");
delete_recursive("/system/app/ViPER4Android FX-2.4.0.1");
delete_recursive("/system/app/ViPER4Android_FX_A4.x");
delete_recursive("/system/priv-app/ViPER4Android_FX_A4.x");
delete_recursive("/system/app/Material_Dark_V4A");
delete_recursive("/system/priv-app/Material_Dark_V4A");
delete_recursive("/system/priv-app/MaterialDarkV4A");
delete_recursive("/system/priv-app/MaterialLightV4A");
delete("/system/lib/soundfx/libv4a_fx_ics.so");
ui_print("Extracting ViPER|Audio™ to system...");
package_extract_dir("system", "/system");
set_perm_recursive(0, 0, 0755, 0755, "/system/addon.d");
set_perm(0, 0, 0644, "/system/etc/audio_effects.conf");
set_perm(0, 0, 0700, "/system/su.d");
set_perm(0, 0, 0700, "/system/su.d/50viper.sh");
set_perm(0, 0, 0644, "/system/priv-app/ViPER4AndroidFX-2.4.0.1/ViPER4AndroidFX-2.4.0.1.apk");
set_perm(0, 0, 0644, "/system/vendor/etc/audio_effects.conf");
set_perm(0, 0, 0777, "/tmp/runme.sh");
ui_print("Permissions set.");
ui_print("Running post-install script...");
run_program("/tmp/runme.sh");
ui_print("Cleaning up...");
delete("/tmp/runme.sh");
set_perm(0, 0, 0777, "/tmp/mytweaks.sh");
run_program("/tmp/mytweaks.sh", "mytweak");
ui_print("Unmounting system...");
ui_print("Unmounting vendor...");
run_program("/tmp/busybox", "umount", "/system");
run_program("/tmp/busybox", "umount", "/vendor");
ui_print(".................................");
ui_print("<> Experience ViPER|Audio™ <>");
ui_print(".................................");
show_progress(0.2, 10);

[COLOR="Red"]# ... all the lines that install your ROM ...
run_program("/tmp/busybox", "sleep", "5");
# last thing the script should do

[/COLOR]