diff --git a/python312.changes b/python312.changes
index 4173fd7..2a1f601 100644
--- a/python312.changes
+++ b/python312.changes
@@ -1,3 +1,10 @@
+-------------------------------------------------------------------
+Tue Jul  1 08:19:52 UTC 2025 - Daniel Garcia <daniel.garcia@suse.com>
+
+- Use one core to build doc. This will make sphinx doc build
+  reproducible.
+  bsc#1243155
+
 -------------------------------------------------------------------
 Mon Jun  9 19:41:07 UTC 2025 - Matej Cepl <mcepl@cepl.eu>
 
diff --git a/python312.spec b/python312.spec
index 17fba23..abd35bd 100644
--- a/python312.spec
+++ b/python312.spec
@@ -486,7 +486,7 @@ TODAY_DATE=`date -r %{SOURCE0} "+%%B %%d, %%Y"`
 
 cd Doc
 sed -i "s/^today = .*/today = '$TODAY_DATE'/" conf.py
-%make_build -j1 html
+%make_build -j1 JOBS=1 html
 
 # Build also devhelp files
 sphinx-build -a -b devhelp . build/devhelp