diff --git a/repository/Seaside-Core.package/WAAbstractFileLibrary.class/instance/entityTagFor..st b/repository/Seaside-Core.package/WAAbstractFileLibrary.class/instance/entityTagFor..st
index 6e6237034..e4fa372a3 100644
--- a/repository/Seaside-Core.package/WAAbstractFileLibrary.class/instance/entityTagFor..st
+++ b/repository/Seaside-Core.package/WAAbstractFileLibrary.class/instance/entityTagFor..st
@@ -3,7 +3,7 @@ entityTagFor: aStringOrByteArray
 	| hash base64 |
 	hash := GRPlatform current secureHashFor: aStringOrByteArray.
 	"etags have to be delimited by double quotes"
-	base64 := GRPlatform current base64Encode: hash asByteArray.
+	base64 := GRPlatform current base64Encode: hash greaseAsByteArray.
 	^ String new: base64 size + 2 streamContents:  [ :stream |
 		stream
 			nextPut: $";