# Issues programming ESP12F

I used this wiring schematic for a couple of my ESP8266-12F projects for programming mode:

As I built enough confidence with the module, I decided to go ahead with a PCB design. When I try to upload a sketch, it wouldn't go into programming mode although I think my design is correct. I checked the connections between pads and headers and they all connected. Am I missing something here? Would you please check the connections and let me know of possible cause?

esptool.py v3.0
Serial port COM4'
Connecting........_____....._____....._____....._____....._____....._____...._____

esptool.FatalError: Failed to connect to ESP8266: Invalid head of packet (0xE0)


• I had a similar problem recently. It was due to not enough capacitance on the power supply. Fatten up your gnd and vcc tracks and add a 22uF 25V ceramic capacitor close to the module pads. Note that it is not a good idea to run tracks under the antenna or even the pcb. May 14 at 19:12