Every modem allows only 10 attempts to enter the unlock code. If you or a previous owner guessed wrong 10 times, the modem is hard-locked.

If you generate a code, and the modem rejects it, you have a "New Algorithm" device.

If you find a file labeled "Huawei Modem Unlocker v577," exercise extreme caution. Malware developers often attach popular keywords to viruses. Legitimate, widely trusted tools include:

If the "v577" tool promises to unlock brand new 4G devices offline without a database, it is likely fake.