diff --git a/meta/classes/mirrors.bbclass b/meta/classes/mirrors.bbclass
index 2eb99cd23f..214608736b 100644
--- a/meta/classes/mirrors.bbclass
+++ b/meta/classes/mirrors.bbclass
@@ -1,4 +1,4 @@
-MIRRORS = "\
+MIRRORS += "\
 ${DEBIAN_MIRROR}/main	http://snapshot.debian.net/archive/pool \n \
 ${DEBIAN_MIRROR}	ftp://ftp.de.debian.org/debian/pool \n \
 ${DEBIAN_MIRROR}	ftp://ftp.au.debian.org/debian/pool \n \