To convert X3000 from USB mode to PCie mode

Remove SIM.
Flash to X3000-PCIE firmware.
Go to Modem->Miscellaneous and use the AT Command Terminal to run

AT+QCFG="data_interface",1,1;+QETH="eth_driver","r8125",1;+QCFG="pcie/mode",0

Insert SIM again and reboot router.
Modem will now be in PCie mode.