Modern MT67xx chipsets implement strict hardware-level security. The BROM will refuse to accept or execute any flashing commands unless the connection is "verified." This verification typically relies on:
Replaces only the partitions selected in the checklist. This is the safest option and preserves your IMEI data. sp flash tool support mt67xx verified
Ensure your smartphone is fully powered off. While holding the or Volume Up button (the key combination varies by device manufacturer), connect the phone to your PC via a high-quality USB cable. sp flash tool support mt67xx verified