I created a remote controller with raspberry pi 4 and waveshare 6700X 4G HAT which can receive SIM messages and control a switch based on SMS. I mounted the Pi, HAT, as well as a fan on a metal board. So far everything worked well. A couple days ago, I disassembled everything to replace a new SIM card, then the HAT won’t be able to read SMS messages. I tried to use minicom to test the serial port but can’t type any letter. I tried all settings I can find from online, still can’t type. I have some screenshots attached. Really appreciate if anyone can point me to a correct direction. Thanks.enter image description here