If the software stays stuck on "Waiting for device," your PC is missing proper USB drivers. Download the latest MediaTek/Qualcomm driver signing package, change your USB cable, or plug the cable into a rear motherboard port (USB 2.0 works best).
The screen will immediately ask for the SIM PIN.
A completely free utility used to disable the secure boot protection on MediaTek chips. Once bypassed, companion tools like SP Flash Tool can erase the lock.