When you see someone on discussion boards say running 4.1.2 Android XXEMB1, and you wonder what the person is talking about, well, here is a short and simple explanation.
Basically, the person is saying he/she is running an Android system version 4.1.2. XXEMB1 basically refers the to baseband, in which case, the baseband for this is XXEMB1. If you are not sure what the baseband of your phone is, you can go to Settings>>About Device and scroll to baseband. That will show you what baseband you are running.