A: No. Unlocking via a 16-digit code modifies the permanent NV-RAM. It survives firmware upgrades, factory resets, and even OS changes.
Most ZTE dongles only allow 5 to 10 attempts . If a "low quality" calculator gives you the wrong code, you may permanently lock the device (Hard Lock).
Before discussing the calculator, we must understand the technology behind the lock.
: If you have entered the wrong code too many times (usually 10 attempts), the device may be "hard-locked." Even a correct 16-digit code will not work at this stage.