user-1: I have problem with WDT reset. After reset the device goes on for a boot loop. from the following link https://code.google.com/p/arduino/issues/detail?id=181
It has been mentioned that there is problem with Bootloader because some of them does not support wdt properly.How can i find which version of bootloader is running in my arduino mega 2560 . Which version of bootloader support wdt properly? where these bootloaders can be found?

user60: In all practicality; put a known boot loader on it. Because if it is a problem version you will need to replace it anyways.
The Mega uses STK500 protocol. Which only shows a command to read its type (or signature) and not its version of firmware.
It is a good exercise, but not really worth the time to go deeper into it, as programmers are cheap and or you can use another Arduino as the programmer. 

user2881: The watchdog timer will reset the Arduino in case of a timeout. The way to prevent this from happening is to catch the WDT interrupt.
ISR(WDT_vect)
{
  // do nothing
}

This has nothing to do with the bootloader. The fix suggested in the link above only makes the bootloader detect a reset triggered by a WDT event, and have it not add any delay. This delay is normally needed to see if the usb-host is trying to upload a new program.

-1: <p>I have problem with WDT reset. After reset the device goes on for a boot loop. from the following link <a href="https://code.google.com/p/arduino/issues/detail?id=181" rel="nofollow">https://code.google.com/p/arduino/issues/detail?id=181</a>
It has been mentioned that there is problem with Bootloader because some of them does not support wdt properly.How can i find which version of bootloader is running in my arduino mega 2560 . Which version of bootloader support wdt properly? where these bootloaders can be found?</p>
 60: <p>In all practicality; put a known boot loader on it. Because if it is a problem version you will need to replace it anyways.</p>

<p>The Mega uses STK500 protocol. Which only shows a command to read its type (or signature) and not its version of firmware.</p>

<p>It is a good exercise, but not really worth the time to go deeper into it, as programmers are cheap and or you can use another Arduino as the programmer. </p>
 2881: <p>The watchdog timer will reset the Arduino in case of a timeout. The way to prevent this from happening is to catch the WDT interrupt.</p>

<pre><code>ISR(WDT_vect)
{
  // do nothing
}
</code></pre>

<p>This has nothing to do with the bootloader. The fix suggested in the link above only makes the bootloader detect a reset triggered by a WDT event, and have it not add any delay. This delay is normally needed to see if the usb-host is trying to upload a new program.</p>
