How to connect an ESP8266 using an ESP-01 adapter to an Arduino Uno?
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you can't flash an esp-01 module with this adapter, unless you find a way to connect io 0 to ground in this setup



I have this type of adapter with esp8266 glued. I can't recommend this type of adapter boards. Easier is to use a development board like Wemos or NodeMCU with on-board USB adapter. And they are cheap.

The adapter has the esp-01 2x6 header J2 but the io 0 and io 2 pins were not connected on my version. I patched io 0 to JP2 header to be able to flash the module. On the picture you see a paperclip jumper connecting GPIO0 to ground.