• Important information
  • Sources
  • Magisk
• Installation
  • System requirements
  • Overview
  • Accessing the device shell using ADB
  • Preparing the filesystem
  • Invoking the installation script
• Using Entware
  • Connecting via SSH
  • Installing packages from the Entware repository
• Notes
  • DNS resolution on Android
  • Running Entware init scripts at device startup

Mandatory

• Armv7-A (or newer) architecture-based device
• A rooted Android operating system with a functioning su binary
• Busybox or a similar utility installed in a PATH directory and compiled with FEATURE_WGET_HTTPS=Y so as to provide a working wget applet
• At least one of the following, to provide access to root shell instances running on the device:
  • A working copy of the Android Debug Bridge (adb)—located in a PATH directory, as above—and no older than the version of Android on the device
  • Either the Terminal Emulator for Android or ADB - Local&Remote ADB Shell apps (or their functional equivalent) installed and working as expected
  • A running SSH server on the device, such as SSH/SFTP Server - Terminal or Simple SSHD

Recommended

• Support for init.d/su.d scripts, to start Entware services automatically after boot, or an Android application with this functionality such as Tasker

The installation itself is performed using a POSIX shell script, which makes two critical implicit assumptions about the environment it's executed on:

1. The /opt directory must be writable (at least by the root user), and
2. A reasonably POSIX-compliant shell interpreter can be invoked by calling /bin/sh (typically a symlink to another binary such as ash, dash or bash, but it need not be).

Assuming all of the prerequisites are satisfied, all that remains is to open a shell on the device, download the appropriate installation script and execute it. For a user who had opted to use the Android Debug Bridge on their desktop computer to communicate to an Android device connected via a USB cable, the process would roughly follow this overall course:

Beginning from a terminal window on the computer with an open instance of the computer's shell, begin by invoking a shell on the Android device by first calling adb connect, followed by adb shell. If successful, the command prompt will change in the terminal emulator to now display the device's codename before each command prompt. (If more than one Android device is connected, expand the collapsed section directly below for more information about explicit device selection in ADB.)

With all of the above concerns addressed, invoking the ADB shell in your computer's terminal emulator should result in (roughly) the following output:

> adb shell
  * daemon not running; starting now at tcp:5037
  * daemon started successfully

device_codename:/ $

The most straightforward (but most dangerous) approach to creating a filesystem location for the Entware environment would be to remount the rootfs in read/write mode and simply create the directories there, as in:

device_codename:/ $ su

                    Password:

device_codename:/ # /system/bin/mount -o rw,remount /
device_codename:/ # mkdir /opt /bin
device_codename:/ # ln -s /system/bin/sh /bin/sh
device_codename:/ # /system/bin/mount -o ro,remount /

However, it's much safer to keep the rootfs limited to read-only access and instead use a bind mount to link the /opt folder to another directory stored on an external storage medium, like an SD card or USB flash drive:

💡 Note: Alternatively, you can bind /opt to a new subdirectory in the /data directory, or mount a loopback device associated with a .img raw disk image file.

mkdir /mnt/external_sd/entware.arm
mount -o bind /mnt/external_sd/entware.arm /opt

Next, run the installation script that corresponds to your device architecture.

• For armv7 (32-bit ARM) devices running Linux kernel v3.2 or newer:

  wget -O- https://bin.entware.net/armv7sf-k3.2/installer/alternative.sh | sh

• For aarch64 (64-bit ARM) devices running Linux kernel v3.10 or newer:

  wget -O- https://bin.entware.net/aarch64-k3.10/installer/alternative.sh | sh

• For armv7 (32-bit ARM) devices running a Linux kernel older than v3.2:

  wget -O- https://bin.entware.net/armv7sf-k2.6/installer/alternative.sh | sh

Then you can install and run the Dropbear SSH server:

unset LD_LIBRARY_PATH LD_PRELOAD
/opt/bin/opkg install dropbear
/opt/sbin/dropbear -p 22 -a

For the initial SSH connection to your device, use the default password (12345) for Entware's root user account. Once connected, it is strongly recommended to change the root account password using the passwd command:

# /opt/bin/passwd
  Changing password for root
  
  New password:
  Retype password:
  passwd: password for root changed by root

After connecting to the device via SSH, install the desired packages using opkg. For instance, installing the Midnight Commander filesystem browser/file editor is as simple as:

opkg update
opkg install mc

It has been observed that some Entware binaries do not function correctly without an /etc/resolv.conf file, though the Android operating system itself does not use this common Linux mechanism. Known possible workarounds are:

1. As by default, the /etc directory on Android is a symlink to /system/etc, remount the /system volume in read/write mode and create a symlink at /system/etc/resolv.conf that resolves to /opt/etc/resolv.conf, where the file can be managed much easier. There can be defined your DNS service of choice following the format (shown in the example are the Google Public DNS server IPv4 addresses):

   nameserver 8.8.8.8
   nameserver 8.8.4.4
   

2. Script the replacement of the default /etc⇾/system/etc symlink to one that instead resolves to /etc⇾/data/local/etc for execution each time the device boots. The suggestion of using /data/local/etc is merely that, any other writeable directory would be just as effective, provided it contained symlinks for the contents of both /system/etc/* and /opt/etc/*:

   mkdir /data/local/etc
   chmod 0755 /data/local/etc
   chcon u:object_r:system_file:s0 /data/local/etc
   for i in $(ls /system/etc); do ln -s "/system/etc/${i}" "/data/local/etc/${i}"; done
   ln -s /opt/etc/resolv.conf /data/local/etc/resolv.conf

3. Recompile the libc-package so that it reads DNS definitions from /opt/etc/resolv.conf rather than /etc/resolv.conf. To effect this, download the libc source code and (after applying the current Entware patch set) patch all instances of filesystem objects located under /etc to refer instead to the desired location by using the find and sed commands:

   find -name "*.[ch]" -type f -execdir sed -Ei 's,/etc/,/opt/etc/,g' '{}' \;
   find -name "*.[ch]" -type f -execdir sed -Ei 's,/opt/opt/,/opt/,g' '{}' \;

To run Entware services automatically after the boot sequence is complete, provide for a script that follows the basic template below (with customizations to suit your device, of course) to be executed on startup:

#!/system/bin/sh

unset LD_PRELOAD LD_LIBRARY_PATH

/system/bin/mount -o rw,remount / && {
  /system/bin/chmod 0777 /mnt/external_sd
  /system/bin/mkdir /opt /bin
  ln -s /system/bin/sh /bin/sh
}

/system/bin/mount -o ro,remount / && {
  /system/bin/mount -t ext2 -o rw /dev/block/mmcblk0p1 /mnt/external_sd
  /system/bin/mount -o bind /mnt/external_sd/entware.arm /opt
}

/opt/etc/init.d/rc.unslung start

exit 0