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 e

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 or adding the following 2 lines to a profile in ~/.aws/config request_checksum_calculation=when_required response_checksum_validation=when_required Or just pin your AWS SDK to version before the following. <https://github.com/aws/aws-sdk-go-v2/blob/release-2025-01-15/service/s3/CHANGELOG.md#v1730-2025-01-15 https://github.com/aws/aws-sdk-go-v2/blob/release-2025-01-15...> <https://github.com/boto/boto3/issues/4392 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/1.37.0/CHANGELOG.rst#L19> <https://github.com/aws/aws-cli/blob/2.23.0/CHANGELOG.rst#2230 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-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-net/releases/tag/3.7.963.0> <https://github.com/aws/aws-sdk-php/releases/tag/3.337.0 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.