The Huawei E173u-1 is a 3G USB dongle typically locked to a specific Network Service Provider (ISP). This lock restricts the device from accepting SIM cards from competing carriers. "Unlock firmware" generally refers to two distinct processes: and Flashing Custom Firmware .
Look at the sticker underneath the modem casing. Ensure it explicitly reads E173u-1 . Do not flash E173s-1, E173s-2, or E173u-2 firmware on this device. Huawei E173u-1 Unlock Firmware
If the modem prompts for a code when you insert a "foreign" SIM card: Insert a SIM card from a different carrier. The Huawei E173u-1 is a 3G USB dongle
If your modem has firmware version , it may be locked down to prevent flashing. Look at the sticker underneath the modem casing
Step-by-Step Guide to Flashing Huawei E173u-1 Unlock Firmware Step 1: Download the Required Tools
: Take out the SIM card and MicroSD card from the modem before plugging it in.
Give your older 3G hardware a second life as a backup internet source or an SMS gateway for DIY projects like Raspberry Pi servers. Understanding Firmware Unlocking vs. IMEI Code Unlocking