diff --git a/manifest/schema2/builder.go b/manifest/schema2/builder.go
index 44b94eaa..ec0bf858 100644
--- a/manifest/schema2/builder.go
+++ b/manifest/schema2/builder.go
@@ -46,6 +46,9 @@ func (mb *builder) Build(ctx context.Context) (distribution.Manifest, error) {
 	m.Config, err = mb.bs.Stat(ctx, configDigest)
 	switch err {
 	case nil:
+		// Override MediaType, since Put always replaces the specified media
+		// type with application/octet-stream in the descriptor it returns.
+		m.Config.MediaType = MediaTypeConfig
 		return FromStruct(m)
 	case distribution.ErrBlobUnknown:
 		// nop