I recently had the Arduino IDE notify me of available boards updates, so I updated. Since then when I try to upload to my Nanos it fails:
avrdude: stk500_recv(): programmer is not responding avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x01 avrdude done. Thank you. Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.
I installed Arduino IDE 1.0.6 and found that I can upload to all my Nanos with that IDE version.
How can I upload to my Nanos using Arduino AVR Boards 1.6.21?