From
here:
Nikon D2X firmware version 2.0
- H 0.3 (equivalent to ISO 1000) and H 0.7 (equivalent to ISO 1250) if using EV steps of 1/3rd steps in the Custom setting b2 or H 0.5 (equivalent to ISO 1100) if using EV steps of ½ steps in the Custom setting b2, have been added between the ISO 800 and H 1 settings in the ISO menu.
- Autofocus subject acquisition and tracking performance has been improved.
- A Black-and-white (sRGB) option has been added to the Color mode option in the shooting menu.
- A new Trim function has been added to the shooting menu.
- Up to 3 custom tone curves can now be downloaded to the camera for use with the Custom Tone compensation option.
- Nikon Capture 4 (Ver. 4.4.2) Camera Control or Camera Control Pro with Ver. 1.1.1 and later is required to download 3 custom tone curves to the camera.
- An Image authentication option has been added to the setup menu.
- The optional Image Authentication Software is required to authenticate images.
- A Save/load settings item has been added to the setup menu.
- The Mirror lock-up option in the setup menu has been modified to function with battery power as well as AC-adapter power.
- The Lock-On option in the CSM menu now offers 4 options: Long, Normal (default), Short, and Off.
- Max. sensitivity and Min. shutter speed options have been added to the ISO auto menu.
- The Maximum shots option in the CSM menu has been updated to support a maximum setting of 60 shots.
- The FUNC. button item in the CSM menu has been divided into 2 separate items labelled FUNC. button and FUNC. + command.
- A Recent settings item has been added to the setup menu.
- The shooting data of an image in the playback photo-information display now includes. Focus mode (S/C/M) and Vibration reduction* (on/off)
- Displayed only when the image was captured with a VR lens.
- Latitude and longitude GPS data now displays up to 3 digits* for each segment.
- 3-digit display may not be possible with some GPS devices.
- A compass bearing is displayed in the GPS data, if used with a GPS device is equipped with digital compass.
Lots more information
here and also a discussion of your question
here.