Hello! So I designed a custom PCB using a ESP32-S3 Mini but am getting repeated issues with flashing to it. I am able to flash to it once I enter bootloader mode, flash, reset, and then the code I uploaded runs. But if I edit anything and reupload, it again errors when trying to upload. So I AM abl…

We need to see a JPEG image of the schematic of our PCB.

Nobody wants zip-files so no loss.

As a new user Im not allowed to have 3+ images, so here is one last schematic photo in the reply [image]

First try a 10k pull-up resistor on pin 4 IO0 [IMG_3846]

Hmmm... still the same issue arises even when I have attached the 10k pull up resistor [image] Im sure its not the connection itself, I proped connectivity between the 3v3 side of the resistor & other 3v3 pads and that was connected, and the button connection to the resistor was also good. Any o…

Custom ESP32 Board - Repeated Flashing Error

Projects General Guidance

crimsonbaba January 12, 2025, 1:11am 7

So, I tried it on a mac and it uploaded fine! So I guess I will be switching to a mac now

Topic		Replies	Views
Was able to upload to ESP32S3 once, but not able to upload anymore Uploading	6	259	November 6, 2025
Issue with uploading code to ESP32 board: "Unable to verify flash chip connection" Uploading	17	9652	May 15, 2025
ESP 32 code not uploading Uploading	8	852	February 27, 2026
Esp32 A fatal error occurred: Unable to verify flash chip connection (No serial data received.). Failed uploading: uploading error: exit status 2 Uploading	7	7762	March 13, 2025
''This error originates from pySerial. It is likely not a problem with esptool, but with the hardware connection or drivers" Uploading	3	158	November 19, 2025

Custom ESP32 Board - Repeated Flashing Error

Related topics