I can't seem to get my mega 2560 into DFU mode. Either that or I'm doing something wrong in Atmel Flip. I think its a rev 1 but I'm not totally sure. I've attached wires to the reset pads for the 8u2 so I can connect them easily, and when I do the device disappears form the Arduino com list, but I cant get Atmel Flip to connect to it. It says "AtLibUsbDfu.dll not found" when I try to connect it.
I've read that I may need to attach a resistor to the HWB, but I don't know where that is.
Here's the front and back of my board to help identify which revision it is, since I'm not sure.
I eventually figured it out so I'll record what I did here in case anyone has this problem in the future.
After finally identifying it as a rev 1, I adapted a guide for the Uno rev 1. Below is another picture of the back of the board, with 2 pads circled in red. To get the board into DFU mode, first plug it into the computer via the usb cable, then jump and hold the 2 pads in red, then jump the two pads that I attached wires to in the first image. Disconnect the two pads with wires, then disconnect the two circled in red.
The drivers that installed after this were not for the 8u2 chip, but they worked anyway. In Atmel Flip select the device as the other chip, not the 8u2.
Interesting. Thanks for the update.