This tool can be used to verify the validity of header checksums in Sega Master System ROM dumps.
Note that some Game Gear and Japanese releases tend to have invalid values as their BIOSes did not check the validity of the checksum.
Based on MSChecksumFixer by Daniel Hall (Dandaman955) but with the checksum writing removed, as we don't want "corrected" versions showing up as those are usually bad dumps.
See COPYING file for license.