Device design is similar to Aoycocr Power Monitoring Plug X10S. Opened the unit by separating glued together plastic parts of the shell, then soldered 5 wires to the following points:
- Main PCB U2 pin 1 (ground)
- Main PCB U2 pin 2 (+3.3V)
- Main PCB LED1 anode, closest to D1 (RXD)
- Daughterboard U2 pin 26 (TXD)
- Daughterboard U2 pin 15 (GPIO0)
Connected power and serial lines, grounded GPIO0, and was able to read the flash and program tasmota.bin.