Firmware for the H168N is highly region-specific. Using the wrong file your device.
Older versions of the V2.2 firmware (including PK1.2T5 and PK1.1T) are flagged for the following: zxhn h168n v22 firmware update download fix
or your specific ISP's website (e.g., MTS, WE, Wind) for the latest "bin" or "trx" files. Automatic Updates Firmware for the H168N is highly region-specific
ZTE does not host public firmware for ISP-locked devices. You must obtain it from: zxhn h168n v22 firmware update download fix