I guess some details of the update would help LOL. It's a nice improvement on battery life IMO.
The remaining battery charge is now accurately detected for Rechargeable Li-ion Battery EN-EL14a.
With A firmware ver. 1.01/B firmware ver. 1.01 or earlier, the number of images that can be captured (battery life) when an EN-EL14a is used is less than when an EN-EL14 is used. By upgrading A firmware to ver. 1.02 and B firmware to ver. 1.01, EN-EL14a performance is maximized so that more images can be captured (battery life) than when an EN-EL14 is used.
Number of shots possible with the EN-EL14a (rated capacity: DC 7.2 V, 1230 mAh; with D5100 A firmware ver. 1.02/Bfirmware: ver. 1.01)
- Single-frame release mode: Approximately 700 shots (CIPA standard*)
- Continuous release mode: Approximately 2650 shots (Nikon standard*)
*See the D5100 User’s Manual for details on test conditions.