diff --git a/weed/s3api/s3_constants/header.go b/weed/s3api/s3_constants/header.go
index 02335e0bd..c8f788bcb 100644
--- a/weed/s3api/s3_constants/header.go
+++ b/weed/s3api/s3_constants/header.go
@@ -87,6 +87,7 @@ const (
 	AmzTrailer              = "X-Amz-Trailer"
 	AmzSdkChecksumAlgorithm = "X-Amz-Sdk-Checksum-Algorithm"
 	AmzChecksumType         = "X-Amz-Checksum-Type"
+	AmzChecksumMode         = "X-Amz-Checksum-Mode"
 
 	// S3 checksum type values (x-amz-checksum-type). A COMPOSITE checksum is a
 	// checksum-of-per-part-checksums ("base64-N"); a FULL_OBJECT checksum is the
diff --git a/weed/s3api/s3api_object_handlers.go b/weed/s3api/s3api_object_handlers.go
index 142665c66..fb5f39660 100644
--- a/weed/s3api/s3api_object_handlers.go
+++ b/weed/s3api/s3api_object_handlers.go
@@ -2238,7 +2238,7 @@ func (s3a *S3ApiServer) setResponseHeaders(w http.ResponseWriter, r *http.Reques
 	// 2. The response covers the full object (no Range header, no partNumber)
 	//    The stored checksum covers the full object; returning it for partial
 	//    responses causes SDK checksum validation failures.
-	if r != nil && r.Header.Get("X-Amz-Checksum-Mode") == "ENABLED" && r.Header.Get("Range") == "" && requestedPartNumber(r) == 0 {
+	if r != nil && strings.EqualFold(lookupHeaderOrQuery(r, parseRequestQuery(r), s3_constants.AmzChecksumMode), "ENABLED") && r.Header.Get("Range") == "" && requestedPartNumber(r) == 0 {
 		if entry.Extended != nil {
 			if algoName, ok := entry.Extended[s3_constants.ExtChecksumAlgorithm]; ok {
 				if checksumVal, ok := entry.Extended[s3_constants.ExtChecksumValue]; ok {