LoRa-E5 GPIO external interrupt problem

Hi.

I am prototyping on LoRA-E5 mini, and have gotten the example LoRa end node code to work. My goal is to count pulses with external interrupt on a GPIO-pin and send the count over LoRa. I am however having trouble getting the interrupt code working with the LoRa example.

I was able to generate an example just containing the GPIO-interrupt with CubeMX, and it works. However when I try to essentially copy the code over to the LoRa example, it doesn’t work. The LoRa code initializes, and sends fine, but when I try to trigger an interrupt on the pin (connecting to ground, trigger on falling edge, internal pullup), nothing seems to happen (there is a debug print in the interrupt) and the entire application seems to hang (no more uart prints of any kind or LoRa messages).

I tried first using GPIO pin PA0/D0, but apparently this is used by a potential button in the LoRa example and am now using PA9/D9, but the results are the same.

Anybody have any ideas on what might be the problem, or how to find out?