diff --git a/Externals.cfg b/Externals.cfg
index 7dfd41a0..cb6237c9 100644
--- a/Externals.cfg
+++ b/Externals.cfg
@@ -64,9 +64,10 @@ local_path = libraries/parallelio
 required = True
 
 [cime]
-tag = cime6.0.156
+#tag = cime6.0.156
+branch = paramgen_py12
 protocol = git
-repo_url = https://github.com/ESMCI/cime
+repo_url = https://github.com/nusbaume/cime
 local_path = cime
 required = True