- powering externally with 18650 lithium battery
- wired the ESP-01 (it's not ESP-01S) with the VCC and CH_PD on OUT +/- directly from TP 4056
- using Hardware Serial TX1 / RX1 with baudrate 115200 and basic sketch SerialPassthrough
- no voltage divider (used before: TIP 120 - MRC 1708)
... ESP still not responding.
I am going to reflash it, maybe there is an issue with the firmware.
Thanks for your posts.