Determine the boot mode parameter of an Amazon EC2 AMI - Amazon Elastic Compute Cloud

Determine the boot mode parameter of an Amazon EC2 AMI

The AMI boot mode parameter is optional. An AMI can have one of the following boot mode parameter values: uefi, legacy-bios, or uefi-preferred.

Some AMIs don't have a boot mode parameter. When an AMI has no boot mode parameter, the instances launched from the AMI use the default value of the instance type, which is uefi on Graviton, and legacy-bios on Intel and AMD instance types.

Console
To determine the boot mode parameter of an AMI (console)

  1. Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/.

  2. In the navigation pane, choose AMIs, and then select the AMI.

  3. Inspect the Boot mode field.

    • A value of uefi indicates that the AMI supports UEFI.

    • A value of uefi-preferred indicates that the AMI supports both UEFI and Legacy BIOS.

    • If there is no value, the instances launched from the AMI use the default value of the instance type.

To determine the boot mode parameter of an AMI when launching an instance (console)

When launching an instance using the launch instance wizard, at the step to select an AMI, inspect the Boot mode field. For more information, see Application and OS Images (Amazon Machine Image).

AWS CLI
To determine the boot mode parameter of an AMI (AWS CLI)

Use the describe-images operation to determine the boot mode of an AMI.

aws ec2 describe-images --region us-east-1 --image-id ami-0abcdef1234567890

{
    "Images": [
        {
         ...
            ],
            "EnaSupport": true,
            "Hypervisor": "xen",
            "ImageOwnerAlias": "amazon",
            "Name": "UEFI_Boot_Mode_Enabled-Windows_Server-2016-English-Full-Base-2020.09.30",
            "RootDeviceName": "/dev/sda1",
            "RootDeviceType": "ebs",
            "SriovNetSupport": "simple",
            "VirtualizationType": "hvm",
            "BootMode": "uefi"
        }
    ]
}

In the output, the BootMode field indicates the boot mode of the AMI. A value of uefi indicates that the AMI supports UEFI. A value of uefi-preferred indicates that the AMI supports both UEFI and Legacy BIOS. If there is no value, the instances launched from the AMI use the default value of the instance type.

PowerShell
To determine the boot mode parameter of an AMI (Tools for PowerShell)

Use the Get-EC2Image Cmdlet to determine the boot mode of an AMI.

PS C:\> Get-EC2Image -Region us-east-1 -ImageId ami-0abcdef1234567890 | Format-List Name, BootMode, TpmSupport

Name       : TPM-Windows_Server-2016-English-Full-Base-2023.05.10
BootMode   : uefi
TpmSupport : v2.0

In the output, the BootMode field indicates the boot mode of the AMI. A value of uefi indicates that the AMI supports UEFI. A value of uefi-preferred indicates that the AMI supports both UEFI and Legacy BIOS. If there is no value, the instances launched from the AMI use the default value of the instance type.