It is based on ESP8266:
As you see I choose the ESP-07 for this, what I've in my parts bin.
I tried to wake up the processor board:
First I loaded the standard Arduino flash test example into it. It was "working", but...
...the result is a massive failure for me:
I bought the ESP-07 modules at the beginning of the ESP8266 era, to play with it. I not even checked the flash size at that time. It has 512K (same as the ESP-01). I changed the flash on the ESP-01, but this has a metal can. Therefore it not worth the effort to change the flash.
Fortunately I've a few ESP-12Es also. So, jumped to my workshop:
Much better:
