diff --git a/buildscripts/build_docker.sh b/buildscripts/build_docker.sh
index b34f9a6e542..fa75c07c1eb 100755
--- a/buildscripts/build_docker.sh
+++ b/buildscripts/build_docker.sh
@@ -4,5 +4,4 @@ set -eu -o pipefail
 readonly buildscripts_dir="$(dirname "$(readlink -f "$0")")"
 docker build -t grpc-java-artifacts-x86 "$buildscripts_dir"/grpc-java-artifacts
 docker build -t grpc-java-artifacts-multiarch -f "$buildscripts_dir"/grpc-java-artifacts/Dockerfile.multiarch.base "$buildscripts_dir"/grpc-java-artifacts
-docker build -t grpc-java-artifacts-ubuntu2004 -f "$buildscripts_dir"/grpc-java-artifacts/Dockerfile.ubuntu2004.base "$buildscripts_dir"/grpc-java-artifacts
 
diff --git a/buildscripts/grpc-java-artifacts/Dockerfile.multiarch.base b/buildscripts/grpc-java-artifacts/Dockerfile.multiarch.base
index 6b670994677..b2f5625afe3 100644
--- a/buildscripts/grpc-java-artifacts/Dockerfile.multiarch.base
+++ b/buildscripts/grpc-java-artifacts/Dockerfile.multiarch.base
@@ -1,7 +1,4 @@
-FROM ubuntu:24.04
-
-# Redirect to the internal mirror to bypass the Kokoro network block
-RUN sed -i 's|http://archive.ubuntu.com/ubuntu/|http://mirror.bazel.build/archive.ubuntu.com/ubuntu/|g' /etc/apt/sources.list
+FROM ubuntu:20.04
 
 RUN export DEBIAN_FRONTEND=noninteractive && \
     apt-get update && \
@@ -12,8 +9,9 @@ RUN export DEBIAN_FRONTEND=noninteractive && \
         curl \
         g++-aarch64-linux-gnu \
         g++-powerpc64le-linux-gnu \
+        g++-s390x-linux-gnu \
         openjdk-11-jdk \
-        pkgconf \
+        pkg-config \
         && \
     rm -rf /var/lib/apt/lists/*
     
diff --git a/buildscripts/grpc-java-artifacts/Dockerfile.ubuntu2004.base b/buildscripts/grpc-java-artifacts/Dockerfile.ubuntu2004.base
deleted file mode 100644
index e987fb3e684..00000000000
--- a/buildscripts/grpc-java-artifacts/Dockerfile.ubuntu2004.base
+++ /dev/null
@@ -1,19 +0,0 @@
-FROM ubuntu:20.04
-
-RUN export DEBIAN_FRONTEND=noninteractive && \
-    apt-get update && \
-    apt-get upgrade -y && \
-    apt-get install -y --no-install-recommends \
-        build-essential \
-        ca-certificates \
-        curl \
-        g++-s390x-linux-gnu \
-        openjdk-8-jdk \
-        pkg-config \
-        && \
-    rm -rf /var/lib/apt/lists/*
-    
-RUN curl -Ls https://github.com/Kitware/CMake/releases/download/v3.26.3/cmake-3.26.3-linux-x86_64.tar.gz | \
-    tar xz -C /var/local
-ENV PATH /var/local/cmake-3.26.3-linux-x86_64/bin:$PATH
-
diff --git a/buildscripts/kokoro/linux_artifacts.sh b/buildscripts/kokoro/linux_artifacts.sh
index 49d9932dfa0..778826b2fc2 100755
--- a/buildscripts/kokoro/linux_artifacts.sh
+++ b/buildscripts/kokoro/linux_artifacts.sh
@@ -17,7 +17,5 @@ trap spongify_logs EXIT
   SKIP_TESTS=true ARCH=aarch_64 /grpc-java/buildscripts/kokoro/unix.sh
 "$GRPC_JAVA_DIR"/buildscripts/run_in_docker.sh grpc-java-artifacts-multiarch env \
   SKIP_TESTS=true ARCH=ppcle_64 /grpc-java/buildscripts/kokoro/unix.sh
-# Use a newer GCC version. GCC 7 in multiarch has a bug:
-#   internal compiler error: output_operand: invalid %-code
-"$GRPC_JAVA_DIR"/buildscripts/run_in_docker.sh grpc-java-artifacts-ubuntu2004 env \
+"$GRPC_JAVA_DIR"/buildscripts/run_in_docker.sh grpc-java-artifacts-multiarch env \
   SKIP_TESTS=true ARCH=s390_64 /grpc-java/buildscripts/kokoro/unix.sh