Can not put Arduino UNO R2's atmega 16U2 into DFU mode

Development Tools IDE 1.x
14

spcomputing:
You were so close, but I like your initiative.

Change

avrdude -p at90usb82 -F -P usb -c avrispmkii -U flash:w:UNO-dfu_and_usbserial_combined.hex -U lfuse:w:0xFF:m -U hfuse:w:0xD9:m -U efuse:w:0xF4:m -U lock:w:0x0F:m

to (at90usb162 for the 16u2)...

avrdude -p at90usb162 -F -P usb -c avrispmkii -U flash:w:UNO-dfu_and_usbserial_combined.hex -U lfuse:w:0xFF:m -U hfuse:w:0xD9:m -U efuse:w:0xF4:m -U lock:w:0x0F:m

...or "-c arduino" if you are using Arduino as ISP. I have successfully re-bootloaded my Uno's 16u2 this way.

It still doesn't work.

Here is what I did. First connect Arduino ISP(it is my UNO R3) and target board(UNO R2), then put following command into command window:

avrdude -P com11 -b 19200 -c avrisp[glow=yellow,2,300] -p at90usb82[/glow] -v -e -U flash:w:UNO-dfu_and_usbserial_combined.hex -U lock:w:0x0F:m

then connect usb cable to R2, computer recognize it as Communication Port(COM4) ( which is not right, but my R3 works well, it shows as Arduino Uno R3(COM11))
I tried to program bootloader into mega328p chip by Arduino IDE, but no response(resp=0x00).

did I do anything wrong?