I’m getting exact same issue as you, have you found any clues? I posted in Quectel EC25 Mini PCIe USIM detection problem (USIM_VDD=0V)
I can also rule out its sim holder for following reasons:
- I have around 100 terminals of 2 different models both with EC25, but different kind of SIM tray, both experience this issue
- I also seen many times a commandline remote reboot fixed this issue, it can’t be loose connection
Sim circuit is same as reference design. I can’t flash firmware nor have a scope on hand.