The BMW E46 navigation is not as complicated as many think, but it it is tough to find information on it. This page should help with centralizing the information for the navigation.
There are two basic software components to the BMW Navigation system. The first component is the Operating System (OS) software and the other is the Map Software. There are four generations of the navigation computer: MKI, MKII, MKIII and MKIV.
BMW Navigation OS Files
BMW Navigation OS - v32 (Original) (8 downloads)
BMW Navigation OS - v31 (Original) (213 downloads)
BMW Navigation OS - v30 (Original) (199 downloads)
BMW Navigation OS - v29 (Original) (194 downloads)