My Thinkpad X260 hackintosh has 10.14.6 running and almost everything works ok so far except Sierra EM7455 WWAN adapter.
Guess I'm not the first one who faced this problem. Long story short - modem is able to detect a SIM card, successfully register itself on GSM network etc but for some reason unable to connect. It gives an ERROR and that's all. AT+CEER explains nothing and ADB feature seems disabled so it's impossible to debug it further. Btw it works pretty well in Linux.
I had spare HUAWEI ME906E M.2 WWAN card branded as HP LT4112 somewhere and decided to try it out. And of course got slapped by Lenovo BIOS white-list 'feature'. It was said to be removed in recent laprop models but looks like it's true for WAN slot only.
There were two options: Remove BIOS white-list by patching BIOS chip itself with external programmer or try to change USB VID/PID of the card to some of the white-listed ones.
The first option was not my case as it turned out that X260 has WSON form-factor BIOS chip and m