Arduino Mega 2560 R3 refuses to enter DFU mode

Hello,
firstly, thanks for the attention
secondly, here’s the problem
I have this new Arduino I have bought recently and I was going to use it with Unojoy so as to make it be recognized as an USB device; the problem is that I can’t manage, for the life of me, to get it into DFU mode. I have been shorting the first two pins of the 6x2 header close to the USB for many times and I do manage to get it to reset, but it always pops back up as Arduino 2560 Mega in the control panel and in the device management menu. Any kind of help would be appreciated!

Your Arduino MEGA may have been loaded with the USB Serial firmware and not the combined DFU + USB Serial. To install the DFU firmware you will need an ISP device.

You can get a USBasp from eBay for less than $4 with shipping. It comes with a 10-pin ICSP cable so you will need to buy or make a 6-pin ICSP adapter. You can order one for about another $4.

johnwasser: Your Arduino MEGA may have been loaded with the USB Serial firmware and not the combined DFU + USB Serial. To install the DFU firmware you will need an ISP device.

You can get a USBasp from eBay for less than $4 with shipping. It comes with a 10-pin ICSP cable so you will need to buy or make a 6-pin ICSP adapter. You can order one for about another $4.

Many thanks, this was really helpful! So just to make sure, can I use Atmel Flip after having installed USB drivers to burn the .hex for the combined serial + dfu for my Arduino 2560? Or do I use another kind of software?

Although this post is outdated, I'm having this same exact issue as the original poster. The board I have is a Mega 2560 R3 by Elegoo (www.elegoo.com)

Once I acquire a USBasp and 10 to 6 pin adapter, where can I find instructions to load the combined DFU + USB Serial firmware?

Thanks!

Update; While finding a USBasp with a 10-pin to 6-pin adapter is easy enough, I can't find clear instructions on where to connect the adapter on the Mega 2560 (I suspect the same 6 pin connector as used to reset), and how to upload the "combined DFU + USB Serial" firmware, and where to aquire the firmware (although again, I suspect it's this file located in my Arduino directory, "E:\Arduino\hardware\arduino\avr\firmwares\atmegax xu2\Arduino-COMBINED-dfu-usbserial-atmega16u2-Mega2560-Rev3.hex".

So, could someone please verify my theories.

The particular Mega2560 (Elegoo, www.elegoo.com) likely did not come with the "combined DFU + USB Serial firmware"? I connect the "10-pin to 6-pin adapter" to the same connection as used to reset/flash, as shown above? The above hex file is correct?

And lastly, how do I flash the "ATMega16U2" chip?