To understand the demand for unlock firmware, one must understand the business model of the ISP. When a provider sells or gives away a router like the B311-221, they subsidize the hardware cost. To ensure they recoup this investment, they implement a "SIM lock." This is a software restriction that prevents the router from accepting a SIM card from a competing network.
Using the tool:
Go to > System > Device Information to see the current version. Huawei Global Support Updating Firmware
It looks like you’re searching for an or method to remove carrier restrictions from a Huawei B311-221 router (often locked to providers like Vodafone, T-Mobile, O2, or others).