This is a trick for ROOT USERS ONLY for enable the hidden/secret option in the settings for set the default install location.

1. Is required SQLITE EDITOR or a program like this.

2. With a file explorer like
 ES FILE EXPLORER or ROOT EXPLORER or directly by sqlite editor go in the system in the folderdata/data/com.android.providers.settings/databases and open the file settings.db in sqlite editor mode.

3. Now select
 system for open the tab, then search under name label for the set_install_location string, then at the right ofset_install_location under the value label there's the value 0, now keep hold the string with the value 0 for open the options menù, then select edit field for edit it, now change the value from 0 to 1 and save, then exit, and then reboot the device for apply the changes.