(which use QCN files to store IMEI) are not compatible with the L850-GL. Known Approaches and Limitations 1. The AT Command Method (Rarely Successful)
For a typical user, the IMEI of a Fibocom L850-GL is immutable. fibocom l850gl change imei
The AT+EGMR (Enhanced Generic Model Reset) command is used on older Qualcomm or MediaTek chips. The Intel XMM 7560 inside the L850-GL uses a proprietary, manufacturer-locked interface. Even if you send the command via a terminal (PuTTY, minicom, or RealTerm), the modem will return: (which use QCN files to store IMEI) are