Without a SIM, you lose carrier provisioning — but that’s fine for development and testing. Always double-check your device’s bootloader unlock policy before starting.

: Go to Settings > About Phone and tap Build Number 7 times.

Wait the required period (usually 168 hours) and unlock via PC.

Connect to Wi-Fi so the phone can ping Google’s servers to enable the OEM Unlocking toggle.

This is risky and requires chipset-specific knowledge.