Uploaded file integrity check failed with S3 and multipart

When uploading a file which need a multipart upload; the response etag is not calculated the same way as a the simple upload.

Instead of a MD5 of the file; the etag is calculated using:
ETag = MD5(Sum(p \in numberParts, MD5(PartBytes(p))) + "-" + numberParts

see: https://forums.aws.amazon.com/thread.jspa?messageID=456442