Double checked again. ( https://cdn.sparkfun.com/datasheets/IoT ... eet_en.pdf page 16 section 2.4) All of these pins have the "right" internal pull-up and pull-down resistors.tve wrote: ↑Mon Jan 27, 2020 5:12 amAlso, I see no "strapping" resistors, e.g. on io12, io15, io2, io5. These could have any value if they're floating and could work on a good day and break on a bad one. Please refer to section 2.4 "Strapping Pins" of the esp32 datasheet. Your hardware design needs some serious updates...
I have also checked the so called "cross bjt" schematic, used on nodemcu. It is used on those boards because they want to be compatible with the arduino IDE. Arduino uses both DTR and RTS for flashing, but this does not work with ESP chips. By using this "cross bjt" schematic with the 1uF cap between GND and reset pins, the ESP chip can also be correctly reseted when DTR + RTS is kept high at the same time. But this is for compatibility with the arduino IDE only. When using esptool, it is not required. You can check in the source code of esptool.py here:
https://github.com/espressif/esptool/bl ... ol.py#L463
It does the 100msec delay from software code, and it never turns on both lines at the same time.
My conclusion is that my board schematic is just fine. There is something else causing the problem.