diff --git a/Dockerfile--rockylinux_10.tmpl b/Dockerfile--rockylinux_10.tmpl
index ed1d068..4a3de07 100644
--- a/Dockerfile--rockylinux_10.tmpl
+++ b/Dockerfile--rockylinux_10.tmpl
@@ -9,6 +9,10 @@ ARG PYTHON_VERSION=3
 # --------------------------------------------- base1
 FROM rockylinux/rockylinux:10 AS base1
 
+# STEP 1: Fix the root cause (unstable mirrors). Switch to the official CDN.
+RUN sed -i 's/mirrorlist=/ #mirrorlist=/g' /etc/yum.repos.d/rocky*.repo && \
+    sed -i 's/#baseurl=http:\/\/dl.rockylinux.org/baseurl=https:\/\/dl.rockylinux.org/g' /etc/yum.repos.d/rocky*.repo
+
 # In RHEL 9/10, the repository for dev packages is called CRB (instead of powertools)
 RUN dnf install -y 'dnf-command(config-manager)' && \
     dnf config-manager --set-enabled crb
diff --git a/Dockerfile--rockylinux_9.tmpl b/Dockerfile--rockylinux_9.tmpl
index 88b0559..1089173 100644
--- a/Dockerfile--rockylinux_9.tmpl
+++ b/Dockerfile--rockylinux_9.tmpl
@@ -40,6 +40,10 @@ RUN /usr/libexec/openssh/sshd-keygen rsa && \
 # --------------------------------------------- base2_with_python-3
 FROM base1 AS base2_with_python-3
 
+# STEP 1: Fix the root cause (unstable mirrors). Switch to the official CDN.
+RUN sed -i 's/mirrorlist=/ #mirrorlist=/g' /etc/yum.repos.d/rocky*.repo && \
+    sed -i 's/#baseurl=http:\/\/dl.rockylinux.org/baseurl=https:\/\/dl.rockylinux.org/g' /etc/yum.repos.d/rocky*.repo
+
 # Rocky 9/10 installs python3.9 or higher (depending on the repository)
 RUN dnf install -y --setopt=retries=10 --setopt=max_parallel_downloads=10 --allowerasing \
     python3 \