The most likely cause of frying the chip with dual-powering is poor design. Early Chinese modules are prone to all sorts of failures due to "user error". Original clone WROOM-based DevKit boards, for example, would pop when you connected the ground from the 3.3V side to the ground of the 5V side. T...

I found https://www.reddit.com/r/esp32/comments/bwgn1q/how_to_power_a_lolin_d32_externally_from_a_dc/ which points to https://www.youtube.com/watch?v=yZjpYmWVLh8 which points out that there is an EN pin that can disable the regulator so you can supply 3.3V. You are right, the diagram is hard to fol...

I regularly power modules via external power and plug in and out the on-board USB to flash with no issues, ever. But then, my regulated external power goes in the 3.3V pin. I wouldn't have thought to put 5V on the 5V USB pin, because that's crazy! Well, it's not that crazy, all ESP32 boards I've bo...

I don't know about wemos/lolin, but the dev kit c shows a blocking diode between the laptop/usb supply and the EXT_5V pin. The usb 5V supply is frequently not enough amps to support wifi without an external 5V supply, so I've been using both supplies with the random devices I get from amazon. I'd b...

You have connected two 5V power supplies to the board (power supply + laptop USB) at the same time? Yes, I have. 5V from battery and voltage regulator, and sometimes I connect the USB to my laptop which indeed supplies 5V also. And yes, the 2 5V are not exactly the same so it could cause a small cu...

1. pull GPIO0 low 2. reset chip by pulling EN low (or removing power) 3. start chip by releasing/pulling up EN (or supplying power) 4. wait a few ms, then you can release GPIO0 5. the ESP should now be in "upload" mode waiting for firmware over serial Now that i've figured out how to flash around a...

1. pull GPIO0 low 2. reset chip by pulling EN low (or removing power) 3. start chip by releasing/pulling up EN (or supplying power) 4. wait a few ms, then you can release GPIO0 5. the ESP should now be in "upload" mode waiting for firmware over serial With RST, I was getting: rst:0x1 (POWERON_RESET...

A couple of thoughts. Have you removed the USB to serial chip? The damaged USB to Serial chip could be driving the pins on the ESP. Maybe the pins on the ESP were also damaged and you will not be able to program the ESP. Thanks for the thought. no, I have not, it's beyond my chip surgery skills If ...

I have now 5 of those that got their USB damaged in a way that it will power from USB, but the usb-serial chip is dead, so I can't flash them the normal way anymore. This seems to be done by some board I have, once I plug a new working one into it, the USB serial chip seems to get destroyed. I have ...

Hi Marc, I'm afraid this isn't possible. The "MMU" in ESP32 is limited to cache access (PSRAM and flash only), it's not possible to remap internal memory access. Do you have 224KB of free contiguous space immediately on boot (after other memory is reclaimed by the bootloader?) If yes, then you coul...