Arduino DUE - Firmware USB upgrade

There seems to still be sold on eBay some DUE boards with know USB firmware issue as described here:

I've tried to upgrade the USB firmware of the DUE following step by step what is recommended from these pages, in my case using a arduino MEGA 1280 but after arduino MEGA 2560:``

The IDE I'm using is 1.5.8, after connecting the DUE's ICSP to the SPI pins of the MEGA then powering the DUE from the MEGA's GND and +5V, both boards power OK when USB connecting the MEGA to my MacBook Air.

After that, I've uploaded the ArduinoISP example sketch from the 1.5.8 and uploaded successfully to my MEGA.

Lastly i've launched a Terminal window from my MacBook Air to launch the AVR dude special script:

/Applications/ -C/Applications/ -c arduino -P /dev/tty.usbserial-A6008igj -b 19200 -p m16u2 -Uflash:w:16u2.hex:i

Unfortunately the AVRdude says the following:

avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x15
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x15

avrdude: stk500_getparm(): (a) protocol error, expect=0x14, resp=0x14

avrdude: stk500_getparm(): (a) protocol error, expect=0x14, resp=0x01
avrdude: stk500_initialize(): (a) protocol error, expect=0x14, resp=0x10
avrdude: initialization failed, rc=-1
         Double check connections and try again, or use -F to override
         this check.

avrdude: stk500_disable(): unknown response=0x12

avrdude done.  Thank you.

Maybe someone could help or guide

OK now it works wonderful, I totally forgot at a 10uF capacitor between the RST and the GND of the MEGA acting as an ISP programmer :smiley: