You must own the hardware. Unlocking a leased or rented modem is illegal. Furthermore, using an unlocked modem for illegal SMS bombing or SIM box fraud (bypassing international termination rates) is a felony in most jurisdictions.
Some unlockers do not modify the firmware. Instead, they calculate the unique 8-to-16-digit NCK using the modem’s IMEI. The algorithm is often proprietary to the modem manufacturer (e.g., a XOR checksum or MD5 hash truncation). The unlocker sends this code via AT commands: AT+CPIN="NCK_CODE" . Gsm Multi-hub Modem Unlocker
: A "multi-hub" tool often refers to software that can manage or unlock multiple devices connected to a computer at once, or one that supports a broad "hub" of different manufacturers like Huawei, Alcatel, LG, and ZTE. Key Features of Popular Unlocking Tools You must own the hardware