ESP32-C3 - Can not upload to blank boards

[Rosdayle]

Hi all,

I have been trying to solve an issue for the past few days with little to no change in my results.

For context, this is my second batch of these custom esp32 c3 boards.
The first batch had a small hurdle where I had to play with the drivers in zadig, and plug in the esp32 boards when my visual studio platform said "Looking for upload port...." This was only for the first time flashing, any future uploads don't require the upload trick

The second batch is causing me a lot of headaches, I have messed with Zadig countless times. Reinstalled drivers. Did the same on another machine. Even updated python and pyserial. To no success.

- The error I receive when trying to do the upload trick of plugging it in while it says "Looking for upload port..."

A fatal error occurred: Could not open COM6, the port doesn't exist
*** [upload] Error 2


- The error I receive when trying to do an upload with the esp plugged in
Auto-detected: COM6
Uploading .pio\build\esp32c3\firmware.bin
esptool.py v4.5
Serial port COM6
A fatal error occurred: Could not open COM6, the port doesn't exist
*** [upload] Error 2


Other notes of interest

- Platformio devices LIST (From main machine)
Description HARDWARE
Interface 2 USB VID:PID=303A:1001 SER=68:67:25:96:48:BC LOCATION=1-1.1:x.2
Interface 0 USB VID:PID=303A:1001 SER=68:67:25:96:48:BC

- Platformio devices LIST (From second machine)
Description HARDWARE
Interface 2 USB VID:PID=303A:1001 SER=68:67:25:96:48:BC LOCATION=1-1.1:x.2
Interface 0 USB VID:PID=303A:1001 SER=68:67:25:96:48:BC LOCATION=1-1.1:x.0


- The first batch (with firmware already loaded on them) can be flashed with no issues

- Esp 32 c3 module markings (There has been no change to the BOM or the PCB)
Batch 1 is labelled "xxh4"
Batch 2 is labelled "m4h4"

- PCB schematics for reference
https://drive.google.com/file/d/1ActGEm ... sp=sharing

- Visual studio firmware for reference
https://drive.google.com/file/d/1tksoyl ... sp=sharing

I'm honestly at a dead end here, and appreciate any help

[ESP_Sprite]

Can you try grounding the IO0 pin on the MCU while booting? It's known that C3 chips with a blank flash will go into a bootloop where the USB port periodically disappears; grounding IO0 gets out of that; if you manage to catch the chips in between boots it'll also work.

[Rosdayle]

I did something similar after making this post. I considered it a bit of a risk. But I bridged after the resistor GPIO9 (R12 in the schematic) to ground with tweezers and managed to load firmware into it. After specifying Interface 0 to be the upload port.

So technically in a way, the problem got solved buuuut just not the way I hoped it would have been. Makes flashing blank boards a bit more tedious. I could add a reset button, however that would pretty much be a "one time use" item as it behaves with no issues once flashed.

I appreciate the reply.

But I'm still kind of curious why these act differently compared to before. mmmmm