The arduino software permits to program your arduino board easily.
With this tutorial you will now read and write all arduino memories.
Step 1: Download MCU-Programmer
MCU-Programmer is an open source tools to read and write micro-controllers memories.
You can download it at https://github.com/devmel/MCU-Programmer/releases
Step 2: Connect the Board
Connect the Arduino board to your computer using the USB cable.
Step 3: Launch the Application
Double-click the MCU-Programmer application (java 1.6 required) you have previously downloaded.
Step 4: Select Your Serial Port
Select the serial device of the Arduino board (COM [1-xx]).
Select Arduino as manufacturer and the board connected (Mega 2560 in picture).
Step 5: Open and Read
Select which memory to use (FLASH, EEPROM or FUSES tab).
Click the "Open" button in the environment.
When "Read" button is available click on it. You have to be fast because some bootloader quit if no action is done.
Wait a few seconds - you should see the RX and TX leds on the board flashing.
Step 6: Done
You can change any bytes and write. If an error occurs, click the "Close" button and restart at step 5.