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

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

  1. Open the Amazon EC2 console at https://console.amazonaws.cn/ec2/.

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

  3. On the Details tab, inspect the Boot mode field.

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).

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

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

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

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.

Expected output

{
    "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"
        }
    ]
}