Please note that I provide information based on available data and this might not be up-to-date or accurate. If issues arise, consider seeking help from official support channels or forums.
At the time, Huawei produced popular USB modems (e.g., E303, E3272, E3372) sold globally through mobile carriers. These carriers often "locked" the modems to their networks, preventing users from inserting a rival SIM card. Frustrated users sought unofficial unlockers.