- Chinese clone. Thanks for the catch. I followed Nick Gammon's instructions, and can update at the 2560 boot loader from a redboard (uno) . I have another issue where a sketch can upload to the 2560 only once with a fresh boot loader.
[Topic: Upload Timeout Error on Mega 2560 - Not Sure What Changed] https://forum.arduino.cc/index.php?topic=83079.msg2450514
- Official 2560 I removed the FTDI driver from Mac OS 10.11, anduse the stock driver. Uno serial is detected, but official 2560 board is not. I see some other posts in the forum on this, but no clues as to a fix or what to do to debug.