I got bit by this a month ago. You can disable the new behavior by setting 2 environment variables

  export AWS_REQUEST_CHECKSUM_CALCULATION=when_required
  export AWS_RESPONSE_CHECKSUM_CALCULATION=when_required

  request_checksum_calculation=when_required
  response_checksum_validation=when_required

<https://github.com/aws/aws-sdk-go-v2/blob/release-2025-01-15...>

<https://github.com/boto/boto3/issues/4392>

<https://github.com/aws/aws-cli/blob/1.37.0/CHANGELOG.rst#L19>

<https://github.com/aws/aws-cli/blob/2.23.0/CHANGELOG.rst#223...>

<https://github.com/aws/aws-sdk-java-v2/releases/tag/2.30.0>

<https://github.com/aws/aws-sdk-net/releases/tag/3.7.963.0>

<https://github.com/aws/aws-sdk-php/releases/tag/3.337.0>

and wait for your S3 Compatible Object store to add a fix to support this.

Oh, I just debugged this 4 hours today and now there is HN post and even better approach in comments….