A software upgrade server capable of upgrading a wireless mobile station via a wireless network. The software upgrade server comprises: 1) a database for storing a plurality of software upgrade files as a plurality of object files and a plurality of image files suitable for use in the wireless mobile station; and 2) an upgrade controller associated with the database for communicating with the mobile station via the wireless network. The upgrade controller receives from the mobile station a select message selecting one of the software upgrade files and a target address associated with an original image file in a memory of the mobile station. The upgrade controller links selected object files to form a dynamically linked library (DLL) file based on the target address. The upgrade controller retrieves from the database a copy of the original image file and generates a delta file corresponding to differences between the original image file and the DLL file and transmits the delta file to the wireless mobile station.