diff --git a/operating-systems/buer.scm b/operating-systems/buer.scm
index 2dd9800..3e723dd 100644
--- a/operating-systems/buer.scm
+++ b/operating-systems/buer.scm
@@ -214,7 +214,7 @@
                       (list "https://ci.guix.gnu.org"
                             "https://berlin.guix.gnu.org"
                             "https://mirrors.sjtug.sjtu.edu.cn/guix"
-                            "http://hydra-guix-129.guix.gnu.org"
+                            "https://hydra-guix-129.guix.gnu.org"
                             "https://bordeaux-singapore-mirror.cbaines.net"
                             "https://bordeaux-us-east-mirror.cbaines.net"))
                     (extra-options `("--max-jobs=8" "--cores=4"))))