SparkFun MicroMod GNSS - ZED-F9P problem

Hello,
I have a **[SparkFun MicroMod GNSS Function Board - ZED-F9P]
a **[SparkFun MicroMod Main Board - Single]
A **[SparkFun MicroMod Main Board - Double]
and a SparkFun MicroMod ESP32 Processor

When I put the GNSS function board and the ESP32 board in the Double board, I can program it, when I put them into the Single board I can’t program it and a I get this error.

rst:0x10 (RTCWDT_RTC_RESET),boot:0x33 (SPI_FAST_FLASH_BOOT)
invalid header: 0xffffffff

Over and over again.

When I boot it without the GNSS Function board it doesn’t give me that error.

When I put the ESP32 and GNSS function board in the double board in any slot it works.

Is my new Single Slot board broken?

Thanks!

If possible, test the voltage at the power supply pins (e.g., 3.3V and GND) . Also, try to power the board via USB and external power sources to see if the issue persists.

Yes, I powered it by battery and USB. I haven’t looked into what those switches do on the dual board, I’m guessing they have something to do with why it sort of works on that and not the single?

The only other thing it might be is a pin/insertion issue on the single board…inspect that area

But, it sounds like there might be a specific pin compatibility issue for the esp32 & gnss board for the single (the double has those switches you mentioned to route data differently)…because they both work, and the esp32 alone works in the single :-/

So while not defective, it may not suit that combination in particular…if you have a different MM processor or function board you might be able to determine for certain

Seems this combination was tested with the old DEV-18575 single board and not the new one.

I guess I need to find out what the difference is. I really need the single board the ESP32 and the GNSS board to work. It’s a small drone, and that’s really the maximum weight it can carry with a helix antenna.

I didn’t expect to have to troubleshoot what seems to be incompatible board combinations.