After weeks of testing and scouring forums, I can confirm this is the that transforms your locked B312-926 into a fully unlocked, band-selectable, multi-carrier beast.
The Huawei B312-926 is a Category 6 LTE router (300 Mbps download, 50 Mbps upload). It supports 2CA (Carrier Aggregation), has two external antenna ports (CRC-9), and runs on a HiSilicon Balong chipset. It is essentially the little brother of the famous B315 and B525. huawei b312926 firmware 10031h192sp9c00 universal work