I wasn't aware of this forum, so my apologies if you didn't receive a solution right away.
To flash the factory firmware:
cd /<<PATH_TO_REPO>>/Core2-for-AWS-IoT-EduKit-Factory-Firmware
idf.py build flash
The tick/pop you hear is the sound of the device rebooting over and over since there's no firmware (after erasing the flash). It's not bricked.
All the links on the instructions as of a week ago all point directly to the us-west-2 region so you don't get taken to your default region by accident. Hoping that helps all users.
Since there appears to be a lot of interest in UIFlow, we will prioritize getting that going in partnership with M5Stack. I really appreciate the feedback.