Perform a factory reset. If that fails, re-flash the firmware, ensuring you use a compatible version for the B866V2 model.
Using the hardware independently of your former ISP. Prerequisites for Unlocking Zte Zxv10 B866v2 Unlock
Unlocking the typically refers to one of two things: bypassing the carrier-locked "walled garden" to use third-party apps or fully unlocking the bootloader to flash custom firmware. Carrier-branded boxes (like those from Claro or MTS) often restrict Developer Options and ADB connections. 1. Bypassing Carrier Restrictions (The "Jump" Method) Perform a factory reset