diff --git a/cmd/tusd/cli/composer.go b/cmd/tusd/cli/composer.go
index 25df09d..70e8eec 100644
--- a/cmd/tusd/cli/composer.go
+++ b/cmd/tusd/cli/composer.go
@@ -43,7 +43,12 @@ func CreateComposer() {
 			if Flags.S3DisableContentHashes {
 				// Prevent the S3 service client from automatically
 				// adding the Content-MD5 header to S3 Object Put and Upload API calls.
-				s3Config = s3Config.WithS3DisableContentMD5Validation(true)
+				//
+				// Note: For now, we do not set S3DisableContentMD5Validation because when terminating an upload,
+				// a signature is required. If not present, S3 will complain:
+				// InvalidRequest: Missing required header for this request: Content-MD5 OR x-amz-checksum-*
+				// So for now, this flag will only cause hashes to be disabled for the UploadPart operation (see s3store.go).
+				//s3Config = s3Config.WithS3DisableContentMD5Validation(true)
 			}
 
 			if Flags.S3DisableSSL {