Arduino YUN: trying to use AVR-GCC + AVR-DUDE

Hi all mates, I'm trying to use pure C (using avr-libc) on my arduino yun (atmega32u4). I've successfully compiled a blinking led example, and now I've an .hex file. The problem is that I'm not able to upload this file on my arduino, here is the output of avr-dude:

avrdude -v -patmega32u4 -cavr109 -P/dev/ttyACM0 -b57600 -D -Uflash:w:main.hex:i avrdude: Version 6.1, (openSUSE Buildservice) Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/ Copyright (c) 2007-2014 Joerg Wunsch

System wide configuration file is "/etc/avrdude.conf" User configuration file is "/home/luca/.avrduderc" User configuration file does not exist or is not a regular file, skipping

Using Port : /dev/ttyACM0 Using Programmer : avr109 Overriding Baud Rate : 57600 AVR Part : ATmega32U4 Chip Erase delay : 9000 us PAGEL : PD7 BS2 : PA0 RESET disposition : dedicated RETRY pulse : SCK serial program mode : yes parallel program mode : yes Timeout : 200 StabDelay : 100 CmdexeDelay : 25 SyncLoops : 32 ByteDelay : 0 PollIndex : 3 PollValue : 0x53 Memory Detail :

Block Poll Page Polled Memory Type Mode Delay Size Indx Paged Size Size #Pages MinW MaxW ReadBack


eeprom 65 20 4 0 no 1024 4 0 9000 9000 0x00 0x00 flash 65 6 128 0 yes 32768 128 256 4500 4500 0x00 0x00 lfuse 0 0 0 0 no 1 0 0 9000 9000 0x00 0x00 hfuse 0 0 0 0 no 1 0 0 9000 9000 0x00 0x00 efuse 0 0 0 0 no 1 0 0 9000 9000 0x00 0x00 lock 0 0 0 0 no 1 0 0 9000 9000 0x00 0x00 calibration 0 0 0 0 no 1 0 0 0 0 0x00 0x00 signature 0 0 0 0 no 3 0 0 0 0 0x00 0x00

Programmer Type : butterfly Description : Atmel AppNote AVR109 Boot Loader

Connecting to programmer: .avrdude: butterfly_recv(): programmer is not responding

What I'm doing wrong ? thanks for the help!