A system and method for generating a second file in a target using a first file and a difference file is provided. The system also provides for a method of transferring a difference file from a source device to the target device in a two or more partial blocks which may be transferred independently and which do not all need to be stored in the target device at any given time. The partial blocks of the subject system each include a plurality of segments, which may each function as a difference instruction to instruct the target device to generate a corresponding portion of the second file. Each of these segments may include a reference to source data within the first data or a reference to new plain data that is provided within the partial block. In this way, the second file may be accurately constructed while minimizing the data transferred.