This is minimal executable ELF binary for ARM, that just returns exit code 42.

Instructions:

$ git submodule init
$ git submodule update
$ make

This will produce binary called tiny, it is 48 bytes long.

If you have rooted android phone with bash in /system/xbin/, you can also use following commands:

$ make install - to install binary through ADB to /system/bin.
$ make test - install and run binary through ADB and check if exit code is correct
$ make uninstall - remove binary from the device

Inspiration from http://www.muppetlabs.com/~breadbox/software/tiny/teensy.html