Unable to GetPassword on AWS EC2 Launched from Windows Server 2016 Custom AMI

We found out that our custom AMI doesn't allow us to enable GetPassword from AWS console on any EC2 launched from it. After reading and some trial and error, we found out that InitializeInstance.ps1 has to be enabled for the next boot.

https://docs.aws.amazon.com/AWSEC2/latest/WindowsGuide/ec2launch.html#ec2launch-inittasks

To be complete, LaunchConfig.json has to have adminPasswordtype  set to Random (default). Then, run the following PowerShell command:

C:\ProgramData\Amazon\EC2-Windows\Launch\Scripts\InitializeInstance.ps1 -Schedule