Firebeetle ESP32 V4.0 IO9 Regression

I recently purchased a few Firebeetle ESP32s to build up more prototypes for a working design. I received v4.0 Firebeetles, while my PCB has been tested with v3.0 Firebeetles. I have a simple switch on IO9 with a pullup that gets connected to ground when the switch is pressed. With the v4.0 Firebeetles the board locks up whenever IO9 is connected to ground. This happens even if the Firebeetle is not connected to anything else. Can you please provide me with a schematic for the v4.0 Firebeetle so I can find the problem with them and try to repair them?