I have an Arduino Uno and a ESP8266. When I try uploading I get avrdude: stk500_getsync() attempt 10 of 10; not in sync resp=0x20.
I can load a simple program with no errors when the ESP8266 is not connected i.e. blink. When I connect the ESP8266 I get the error. I have tried a new cable, hit the reset, and tried a new ESP8266. nothing works. I connected the ESP8266 according to instructions. Bottom right is 3.3v, Top left is gnd, Top right is Rx, Bottom left is TX, and CHPD is connected to 3.3V. Can send pictures if you need,
Hope you can help.
You are doing something wrong.
I currently have a homemade ESP8266 shield (ESP-01) on my Arduino Uno, and I have no problems programming my Arduino Uno.
I was doing something wrong. The wiring diagram I was using showed the RST going from the Arduino UNO to the 3.3V. I changed that to the RST on the ESP8266 to the 3.3V and it works.