Static file system differencing and updating

Systems and methods are provided for static file system (SFS) differencing and updating. The differencing and updating includes portion-level differencing and block-level updating of units of an original image (referred to as blocks). The differencing and updating splits SFS images into portions based on block information and the image structure. A delta file is generated for each portion (portion-level differencing) of the new SFS image; the delta file includes information of differences between the portion of the new SFS image and the portion of the original SFS image to which the new SFS image portion corresponds. The delta files are transferred to a device where the target SFS image of the device is updated block-by-block using information of the delta files. The block-by-block update reconstructs all portions of the new SFS image in a device block in host device RAM and writes the reconstructed block into host device ROM.