This is a follow on question from How to reduce serial speed on Arduino bootloader (optiboot) and on the IDE?
I did manage recompile optiboot bootloader to work at 57600 bps and uploaded it to a couple of ATmega328-PUs. I just changed the
57600L in Makefile and recompiled it.
They worked just fine with my Arduino Single Sided Serial (Severino) and a couple of custom standalone Arduino boards with FTDI-like header.
However, I couldn't program the same MCUs using my Arduino Uno R3. When I try to upload a sketch, avrdude just sits there waiting for a response that doesn't come. The output I got is something like this:
avrdude: Version 5.11, compiled on Sep 2 2011 at 19:38:36 Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/ Copyright (c) 2007-2009 Joerg Wunsch System wide configuration file is "C:\Users\Ricardo\arduino-1.0.5\hardware/tools/avr/etc/avrdude.conf" Using Port : \\.\COM3 Using Programmer : arduino Overriding Baud Rate : 57600 avrdude: Send: 0   avrdude: Send: 0   avrdude: Send: 0   avrdude: Recv: avrdude: stk500_getsync(): not in sync: resp=0x00 avrdude done. Thank you.
Would that have anything to do with the 2nd MCU that acts as the USB driver on the Uno - the ATmega16U2? Do I have to patch it, too?
So, my questions are:
1. Why my recompiled optiboot didn't work with my Arduino Uno R3?
2. What can I do to check what's wrong with the upload process using my new bootloader?