Power off the phone. Hold the Volume Down or Volume Up button (depending on the specific sub-model) and plug in the USB cable.
Click on the "Choose" button next to the Authentication File path in the tool. Select the auth_sv5.auth (or similar) file you downloaded. tecno bb2 auth file new
Found inside the official Tecno BB2 firmware folder. How to Use the Tecno BB2 Auth File Power off the phone
If the phone doesn't turn on, the Auth file helps the PC communicate with the chipset. Select the auth_sv5
Modern MTK (MediaTek) devices like the Tecno BB2 use a secure boot system. This system prevents unauthorized software from modifying the internal partitions. An "Auth File" (Authentication File) acts as a digital handshake between the phone and the flashing software, allowing the tool to write data to the device's EMMC or UFS storage. Why You Need the New Auth File