CASIO calculators have known a few version formats throughout the years. I’ll only speak of the latest version format here.

The versions are usually of the MM.mm.iiii format, ASCII-encoded, where MM represents the major version, mm represents the minor version, and iiii represents the miscallaneous information.

The information digits are automatically filled by the bootcode/OS; do not use these digits as build numbers, or anything else. On dumped OS, the information digits are found as 0000, which means they are calculated at boot time, or after.

The first information digit is the localization information, i.e. for which territory the OS is modified for. Known values are the following:

  • 0: the OS is the international version;
  • 1: the OS has been modified for Australia;
  • 2: the OS has been modified for France;
  • 3: the OS has been modified for North America;
  • 4: the OS has been modified for China;
  • 5: the OS has been modified for Singapour.

The second information digit is the features set for the calculator. Known values for this digit are the following:

  • 1: slim features;
  • 2: all features (fx-9860GII);
  • 3: reduced features (fx-7400GII);
  • 7: no math features (?).

The third information digit is the development status of this build of the OS. It is either 1 if this build is a special or in development 1, and 0 if it is a standard build. As you can guess, the 1 value for this digit is quite rare.

The fourth and last information digit is the platform for which the OS is built. It can take the following values:

  • 0: SH7337/SH7355 microcontroller;
  • 1: SH7305 microcontroller;
  • 2: SH7305 microcontroller with Prizm-specific modules.

For example, the 02.05.2201 could be a standard build of the 02.05 OS for the french Graph 75+E model (or equivalent), with all features enabled.