ARM v4, little endian, soft float, OABI.

This is the "i386 of ARM".  It's an extremely generic arm image that should run
on any arm hardware still in use today (except ARMv7M, which is arm in name
only).

Note: and ARMv5 capable processor can run ARMv4 binaries, ARMv6 can run ARMv5,
and so on.  Each new architecture is a superset of the old ones, and the main
reason to compile for newer platforms is efficiency (faster speed, better
battery life).

The oldest architecture this compatability goes back to is ARMv3 (which
introduced 32-bit addressing), but that hardware is obsolete (not just no
longer being sold, but mostly cycled out of the installed base).

For details, see http://www.arm.com/products/CPUs/architecture.html