ESP32 Always boots in Download mode.

[Ricardo_Davitec]

Hello everybody,
Hope someone's help.
I developed a general purpose board for ESP32. I mounted a few of them without troubles, but I recently got some new esp32-WROON- 32E, and they are not working any more.
Every time we boot the board, it goes into download mode.
Io0 pin is hardware externally pulled up to 3.3 Vdd with a 10K resistor. When I measured the tension on this pin, with the new chips I got 0,96 V. With the old chips, in this pin I have 3.3 V (R28 in schematic). I know that's why the chip goes to download mode.
What I don't know is why it's happening. Some way, internally, the pin seems that is draining current.
The chip looks it's working well, as I can upload codes normally, although the firmware can not run after...
Does anybody know what is happening?

WhatsApp Image 2023-02-09 at 13.16.42.jpeg (104.01 KiB) Viewed 10846 times

Thank You in advance!

[ESP_Sprite]

You only have one board this happens on? Could you have a short, e.g. under the module?

[Ricardo_Davitec]

I have built an entire new circuit board, soldering only the minimal necessary components to test the upload system. Also, I used two more new Esp32. The problem persists. The PCI board was previous used with success. Two of them are still working...
I've tried to use an external pull-up resistor to the 3.3 VDC, with different values such as 10K, 1K, 470R. The behaviour is almost the same.
I connected a voltmeter to the Gpio0 pin to monitor what happens.
If I leave the board unconnected from power for an hour or so, when I turn on the circuit power, Gpio0 goes to 3.3 VDC, remain 3.3 for a few 4 or 5 seconds, then begins to go down in a rate of about 0.2 volts per second and keeps going down until hits about 0.8 VDC.
During this process, if I turn the circuit off and on again, the Gpio0 goes 0Vdc (When off), and returns to the voltage it was immediately before turning it off, continuing going down as before.
Obviously, If I do this when the voltage is below the minimal necessary to guarantee a logic "1" in Gpio0, the chip enters the download mode, as expected.
Furthermore, it happens even if there is no code saved to the ESP32.

[ESP_Sprite]

Sorry, I'm not seeing anything odd in your schematic or in what you tell me that could have caused this behaviour, and I can't say I ever ran into this before.