You do need a SIM card to unlock a bootloader. The primary requirement is a data connection (Wi-Fi is sufficient) for the initial "OEM Unlock" toggle check, and a USB cable/PC for the final unlocking commands.
Pixel phones are the easiest to
Confirm the selection on your phone’s screen using the volume buttons. Type fastboot reboot to finish. Method 2: Unlocking Xiaomi Without a SIM Card how to unlock bootloader without sim card
Leo smiled—there was no data to lose. He pressed the volume up key to confirm. The phone wiped itself clean, reborn as an open canvas, no SIM card required [1, 3]. specific terminal commands for your phone model, or are you stuck on a grayed-out toggle right now? You do need a SIM card to unlock a bootloader
: Power off the phone, then hold Volume Down + Power while booting. Type fastboot reboot to finish
MediaTek (MTK) and some Qualcomm devices where OEM unlocking is grayed out without a SIM.
If it works, great — no SIM needed.