Title:
Methods and Implications of Modifying the IMEI on Fibocom L850GL 4G LTE Modems: A Technical Review
Safe method using Lenovo’s built-in tool (for ThinkPad users):
- Download Lenovo LTE Mobile Broadband Firmware Update Utility from Lenovo support.
- Run as Administrator.
- Look for “Restore IMEI” option (hidden but accessible via command line:
L850-FWUpdate.exe /imei=YOURIMEI). - The tool will write only if the stored IMEI is all zeros.
- Power cycle the laptop (not just restart driver).
- Send
AT+CGSN=1again – new IMEI should appear. - Insert SIM → Try connecting to your carrier (voice/data).
Step 5: Write New IMEI
Open UltraCMT → Select “Intel XMM 7560” → Choose “Write IMEI” → Enter new IMEI → Click Start. A green PASS message indicates success.
Compatibility: Getting the modem to work on data plans that are restricted to specific "approved" devices (like tablets or phones).
1. Introduction
- Fibocom L850GL specs: PCIe/USB interface, firmware controlled via MBIM or AT commands.
- IMEI storage: NVRAM region in the modem’s flash.
- Motivation for change (legitimate only): testing, debugging, or replacing a faulty modem with identical IMEI for carrier compatibility.
To interact with the firmware of an L850-GL, standard Windows drivers are usually insufficient. Intel Flash Tool: Used for flashing low-level binary files. SEC Tool / Engineering Drivers: Special drivers that expose the "Diagnostic Port." Hex Editor:
If you have a module with SecureLevel: 0, users on communities like 4PDA have reported success using the following sequence in a serial terminal:
chipset. Unlike older Qualcomm-based modules that use simple "AT Commands" to change settings, Intel-based modems are more restrictive. Key Hardware Specs Form Factor: Interface: PCIe (not USB-based like many older modems) Intel XMM 7360 Uses signed firmware to prevent unauthorized tampering. 🛠 Required Tools for Modification
