ESP12 shield for M5Stack - Flash your ESP through the M5!
MIT License
M5Stack | ESP12
------------+------------
16 (Rx2) | D1 (TX0)
17 (Tx2) | D3 (RX0)
12 | D0 (FLASH)
13 | RESET
3.3v | VCC
3.3v | D2
3.3v | CH_PD (EN)
GND | GND
GND | D15
Also acts as a serial bridge (115200) after flash timeout.