A firmware data processing system may be operable to allocate a configuration area in the firmware binary image file for customizable settings. During the firmware build process for the firmware binary image file, default configuration information may be inserted into this configuration area. This default configuration information may be either actual default setting values or indicator to use the default setting values. During post-build modification process, a separately created utility application may be operable to read in the original firmware binary image file, select new settings, and insert new configuration information into the configuration area. The utility application may also be operable to create a new firmware binary image file with reproduced checksums or other error detection mechanisms required for the original firmware binary image file, based on the new configuration information in the configuration area.