Can't flash ESP32 Pico D4 on custom FCB board

[marcus.tobias]

Hi @ll,

I am using a custom FCB board with a ESP32 Pico D4 chip. I get a serial connection over UART0 to the ESP32 and if I set GPIO0 to GND it starts in Download Mode and returns:

rst:0x1 (poweron_reset),boot:0x3 (download_boot(uart0/uart1/sdio_rei_reo_v2)) waiting for download

But after, the ESP32 only echo back, what sent to him.

The esptool.py returns:

Connecting...

A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header

Thanks for your help

[ESP_Angus]

In UART download mode, the ESP32 normally doesn't echo anything back. If the echo is really coming from the serial link (not from a "local echo" option in the serial console program) then it may indicate that RX & TX pins are shorted somewhere.

The problem with esptool could be caused by this, or it could be that the RX pin on the ESP32 end is not receiving any serial data which is sent by esptool (ie the serial link is only established in one direction).

[marcus.tobias]

Sorry for the delay. I have tested it. The lines are not connected anywhere. I am not sure, but I think it RX and TX are connected it would cause problems with the handshaking at all.

After watch ing the code of the esptool.py script it requires the esp32 send the same datas back, but the following data result packet is not comming.

[marcus.tobias]

Hi @ll,

I found the problem for myself. I gave the power over the USB-Port. After support the ESP32 with power from serial interface board, everything worked perfect. Thanks to Agnus.

Can close the thread.