Does the following mean that cloudformation is not supported if I need to change t4g to standard mode for burstable instances?
You can launch your instances as unlimited or standard using the Amazon EC2 console, an AWS SDK, a command line tool, or with an Auto Scaling group.
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/burstable-performance-instances-how-to.html
It does not mean that CloudFormation is not supported. You are always better to check CloudFormation documentation addressing that type of questions.
I created an EC2 Instance with unlimited
mode that comes by default
Resources:
EC2Instance:
Type: AWS::EC2::Instance
Properties:
InstanceType: 't4g.medium'
SubnetId: 'subnet-07cc83847cb184254'
SecurityGroupIds: ['sg-0a8d1090cfb961220']
ImageId: 'ami-0006abfd85caddf82'
then updated the Stack adding CreditSpecification:
CreditSpecification:
CPUCredits: 'standard'
and it updated perfectly.