Android Typical Configuration Example Emulated primary, physical secondary (like Xoom)

This is a typical configuration for a device with multiple external storage devices, where the primary device is backed by internal storage on the device, and where the secondary device is a physical SD card.
The raw physical device must first be mounted under /mnt/media_rw where only the system and FUSE daemon can access it. vold will then manage the fuse_sdcard1 service when media is inserted/removed.

fstab.hardware

[physical device node]  auto  vfat  defaults  voldmanaged=sdcard1:auto

init.hardware.rc

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

    mkdir /mnt/media_rw/sdcard1 0700 media_rw media_rw
    mkdir /storage/sdcard1 0700 root root

    export EXTERNAL_STORAGE /storage/emulated/legacy
    export EMULATED_STORAGE_SOURCE /mnt/shell/emulated
    export EMULATED_STORAGE_TARGET /storage/emulated
    export SECONDARY_STORAGE /storage/sdcard1

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

service fuse_sdcard1 /system/bin/sdcard -u 1023 -g 1023 -w 1023 -d /mnt/media_rw/sdcard1 /storage/sdcard1
    class late_start
    disabled

storage_list.xml

<storage
    android:storageDescription="@string/storage_internal"
    android:emulated="true"
    android:mtpReserve="100" />
<storage
    android:mountPoint="/storage/sdcard1"
    android:storageDescription="@string/storage_sd_card"
    android:removable="true"
    android:maxFileSize="4096" />

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