How to Unlock and Install Custom Firmware on the Huawei E8372H-320 (Step-by-Step)
| Error | Likely Cause | Solution |
| :--- | :--- | :--- |
| "Device not found" in Balong Downloader | Drivers not installed or modem not in download mode. | Reinstall Huawei NDIS driver. Re-enter download mode. |
| Flash fails at 2% | Wrong firmware version (e.g., E8372h-153 firmware on a -320). | Find firmware specifically for E8372h-320. |
| After flash, only green light no network | NVRAM corruption. | Flash again, but this time check "Restore NVRAM" with a generic backup. |
| WebUI shows "No SIM" after unlock | SIM contacts dirty or firmware has wrong modem configuration. | Clean SIM. Flash an alternative unlock firmware (e.g., "Balong V7R2 Universal"). |
| Modem stays in "COM mode" after reset | Bootloader glitch. | Use DC-Unlocker to AT^RESET command (AT command: AT^RESET). | e8372h320 unlock firmware install
| Issue | Solution | |-------|----------| | Device not detected in DL mode | Install Huawei Balong driver (use Zadig for WinUSB) | | Flashing stops at 50% | Wrong firmware version – re-download for h-320 only | | No Wi-Fi after flash | Set Wi-Fi in LuCI: country code, SSID, password | | No mobile network | Check APN settings in Interfaces → WAN | | Bricked (no LED) | Short test points to force DL mode and reflash backup | Title How to Unlock and Install Custom Firmware
fastboot (if enabled in current firmware):fastboot devices
fastboot oem reboot-bootloader
Most carrier firmwares disable fastboot, so Method 1 is more reliable. No risk of bricking
To flash, the device must be in download mode (not HiLink mode).
AT^BAND=0,0FFFFFFFF
Huawei Universal Flash Tool. Click "Enter Download Mode". The device will disconnect and reconnect as "Huawei Balong Modem (COM3)".“I bought a cheap used E8372h-320 from eBay. It was locked to ‘Three UK’ or ‘T-Mobile Poland’. I want to use my local SIM. I found tutorials mentioning ‘unlock firmware’ — but they confuse SIM unlock with generic firmware. Now I’m trying to understand the correct sequence: unlock first (using code or paid service), then optionally flash generic firmware. I also hope the custom firmware might fix the broken SMS page or allow me to lock to 4G only.”