Android Typical Configuration Example Emulated primary only (like Nexus 4)

This is a typical configuration for a device with single external storage device which is backed by internal storage on the device.

init.hardware.rc

on init
    mkdir /mnt/shell/emulated 0700 shell shell
    mkdir /storage/emulated 0555 root root

    export EXTERNAL_STORAGE /storage/emulated/legacy
    export EMULATED_STORAGE_SOURCE /mnt/shell/emulated
    export EMULATED_STORAGE_TARGET /storage/emulated

on fs
    setprop ro.crypto.fuse_sdcard true

service sdcard /system/bin/sdcard -u 1023 -g 1023 -l /data/media /mnt/shell/emulated
    class late_start

storage_list.xml

<storage
    android:storageDescription="@string/storage_internal"
    android:emulated="true"
    android:mtpReserve="100" />