Determine the boot mode of an instance - Amazon Elastic Compute Cloud
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Determine the boot mode of an instance

When an instance is launched, the value for its boot mode parameter is determined by the value of the boot mode parameter of the AMI used to launch it, as follows:

  • An AMI with a boot mode parameter of uefi creates an instance with a boot mode parameter of uefi.

  • An AMI with a boot mode parameter of legacy-bios creates an instance with no boot mode parameter. An instance with no boot mode parameter uses its default value, which is legacy-bios in this case.

  • An AMI with no boot mode parameter value creates an instance with no boot mode parameter value.

The value of the instance's boot mode parameter determines the mode in which it boots. If there is no value, the default boot mode is used, which is uefi on Graviton, and legacy-bios on Intel and AMD instance types.

To determine the boot mode of an instance (console)

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

  2. In the navigation pane, choose Instances, and then select your instance.

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

To determine the boot mode of an instance (Amazon CLI version 1.19.34 and later and version 2.1.32 and later)

Use the describe-instances command to determine the boot mode of an instance.

aws ec2 --region us-east-1 describe-instances --instance-ids i-1234567890abcdef0

Expected output

{ "Reservations": [ { "Groups": [], "Instances": [ { "AmiLaunchIndex": 0, "ImageId": "ami-0e2063e7f6dc3bee8", "InstanceId": "i-1234567890abcdef0", "InstanceType": "m5.2xlarge", ... }, "BootMode": "uefi" } ], "OwnerId": "1234567890", "ReservationId": "r-1234567890abcdef0" } ] }