When reversing embedded code, it is often the case that completely different devices are built around a common code base, either due to code re-use by the vendor, or through the use of third-party software; this is especially true of devices running the same Real Time Operating System.
more here...........http://www.devttys0.com/2014/10/a-code-signature-plugin-for-ida/
more here...........http://www.devttys0.com/2014/10/a-code-signature-plugin-for-ida/