In the meantime I tried all possible combinations of different auto boot circuits but always the same result. Can someone help me out?

Hi Angus,

thank you for your answer, I just switched out the R5 and rechecked all pins on the ESP32 since I have no access to an oscilloscope.

As you told, I am getting a response from the ESP32 but nevertheless, still the same problem at upload.

In the image below you can see what I mean (all ...

Hi Angus,
thank you very much for your help!
I just tried both approaches and here are the two capture files:
https://www49.zippyshare.com/v/x9n46WcT/file.html (capture from upload with esptool)
https://www49.zippyshare.com/v/1m4UNLVd/file.html (capture from upload with Arduino IDE)

also I ...

Hello,
I am currently developing a custom PCB for a hobby project and for that I used a Pico-D4 chip and a CP2104 serial chip. As you can see in the schematic, I used a common two-transistor auto boot sequence "selector" circuit for programming.

The problem is that I always get a "timed out waiting ...