diff --git a/diagnostics.yml b/diagnostics.yml
index 03778eaebb..daab98353a 100644
--- a/diagnostics.yml
+++ b/diagnostics.yml
@@ -206,21 +206,6 @@ extends:
       #                          #
       ############################
 
-      - template: /eng/pipelines/build.yml
-        parameters:
-          jobTemplate: ${{ variables.jobTemplate }}
-          name: Ubuntu_20_04
-          osGroup: Linux
-          container: test_ubuntu_20_04
-          dependsOn: Linux
-          testOnly: true
-          buildConfigs:
-          - configuration: Release
-            architecture: x64
-          - ${{ if in(variables['Build.Reason'], 'PullRequest') }}:
-            - configuration: Debug
-              architecture: x64
-
       - template: /eng/pipelines/build.yml
         parameters:
           jobTemplate: ${{ variables.jobTemplate }}
diff --git a/eng/pipelines/pipeline-resources.yml b/eng/pipelines/pipeline-resources.yml
index 6c418d6693..6733c0dadb 100644
--- a/eng/pipelines/pipeline-resources.yml
+++ b/eng/pipelines/pipeline-resources.yml
@@ -53,17 +53,17 @@ extends:
           ROOTFS_DIR: /crossrootfs/arm64
 
       linux_s390x:
-        image: mcr.microsoft.com/dotnet-buildtools/prereqs:ubuntu-18.04-cross-s390x
+        image: mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-net8.0-cross-s390x
         env:
           ROOTFS_DIR: /crossrootfs/s390x
 
       linux_ppc64le:
-        image: mcr.microsoft.com/dotnet-buildtools/prereqs:ubuntu-18.04-cross-ppc64le
+        image: mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-net8.0-cross-ppc64le
         env:
           ROOTFS_DIR: /crossrootfs/ppc64le
 
       linux_riscv64:
-        image: mcr.microsoft.com/dotnet-buildtools/prereqs:ubuntu-22.04-cross-riscv64
+        image: mcr.microsoft.com/dotnet-buildtools/prereqs:azurelinux-3.0-net8.0-cross-riscv64
         env:
           ROOTFS_DIR: /crossrootfs/riscv64
 
@@ -85,10 +85,6 @@ extends:
       test_opensuse_15_2:
         image: mcr.microsoft.com/dotnet-buildtools/prereqs:opensuse-15.2-helix-amd64
 
-      test_ubuntu_20_04:
-        image: mcr.microsoft.com/dotnet-buildtools/prereqs:ubuntu-20.04
-        options: '--env PYTHONPATH=/usr/bin/python3.8'
-
       test_ubuntu_22_04:
         image: mcr.microsoft.com/dotnet-buildtools/prereqs:ubuntu-22.04
         options: '--env PYTHONPATH=/usr/bin/python3.10'