[Barry Chu]

http://nikonrumors.com/2014/04/22/nikon-d4s-firmware-updated-c-1-01-released.aspx/#more-75636

Here is the changelog:

When Custom Setting f1 (Multi selector center button) > Playback mode was set to View histograms, the histogram was not displayed correctly for the image played back in the monitor, even when the center button on the multi selector was pressed, when the following conditions were met. This issue has been resolved.
Image quality was set to NEF (RAW) + JPEG fine, NEF (RAW) + JPEG normal, or NEF (RAW) + JPEG basic.
An option other than "Overview data" or "RGB histogram" was selected for photo information displayed with full-frame image playback.
With full-frame image playback with "Highlights" or "RGB histogram" display selected, image chroma (saturation) changed with flashing of highlights. This issue has been resolved.
When images captured with Color space set to Adobe RGB were enlarged with playback in the monitor, image chroma (saturation) changed. This issue has been resolved.
When Rotate tall in the playback menu was set to On, and an image captured in "tall" (portrait) orientation was enlarged slightly (playback zoom-in button pressed once or twice) with monitor playback, the image did not appear to be very sharp or clear. This issue has been resolved.
With capture of a Compressed RAW image, followed by a Lossless compressed RAW image, with Image quality set to NEF (RAW), the camera was sometimes unable to correctly record the second RAW image. This issue has been resolved.

Important notes for this firmware update:

If you have a Lexar 400x or 1000x CompactFlash memory card, please click this link for information regarding compatibility with your camera.
The firmware cannot be upgraded when Network > Network connection in the Setup menu is set to ON. Be sure to set Network connection to OFF before attempting to upgrade the firmware.
Please be sure to use a FULLY charged EN-EL18 battery or EH-6 AC Adapter with EP-6 Power connector to perform this update


Read more on NikonRumors.com: http://nikonrumors.com/2014/04/22/nikon-d4s-firmware-updated-c-1-01-released.aspx/#ixzz2ze3kOMuu