We use the SixFab 4G Base HATs with a third-party power management board. The GPIO-4 pin mustn’t be pulled to ground, because this will shut down the system. Out of the 13 systems we built, two are experiencing issues. I isolated the issue to the Sixfab modem. When I remove the modem, GPIO-4 is not being pulled low anymore. According to the documentation, GPIO-4 should not even be connected on the Base HAT. Does anyone have a clue what could cause this issue?