diff --git a/.github/workflows/build-test.yaml b/.github/workflows/build-test.yaml
index 4411adf258..68552dfde6 100644
--- a/.github/workflows/build-test.yaml
+++ b/.github/workflows/build-test.yaml
@@ -11,9 +11,6 @@ defaults:
   run:
     shell: bash
 
-env:
-  HOMEBREW_NO_AUTO_UPDATE: 1
-
 jobs:
 
   build:
@@ -115,11 +112,15 @@ jobs:
       run: |
         source .venv/${{matrix.venv-loc}}/activate
         pytest yt --color=yes
+      env:
+        MPLCONFIGDIR: tests
     - name: Run Tests (nose)
       if: matrix.test-runner == 'nose'
       run: |
         source .venv/${{matrix.venv-loc}}/activate
         cat nose_ignores.txt | xargs python -m nose -c nose_unit.cfg --traverse-namespace
+      env:
+        MPLCONFIGDIR: tests
 
   image-tests:
     name: Image tests
@@ -157,6 +158,8 @@ jobs:
                --mpl-results-path=pytest_mpl_results \
                --mpl-baseline-path=tests/pytest_mpl_baseline \
                -rxXs # show extra info on xfailed, xpassed, and skipped tests
+      env:
+        MPLCONFIGDIR: tests
 
     - name: Generate new image baseline
       if: failure()
@@ -164,6 +167,8 @@ jobs:
         pytest yt --color=yes --mpl -m mpl_image_compare \
                --mpl-generate-path=pytest_mpl_new_baseline \
                --last-failed
+      env:
+        MPLCONFIGDIR: tests
 
     # always attempt to upload artifacts, even
     # (and especially) in case of failure.
diff --git a/tests/ci_install.sh b/tests/ci_install.sh
index cb1daa5460..a62e18a839 100644
--- a/tests/ci_install.sh
+++ b/tests/ci_install.sh
@@ -1,28 +1,16 @@
 set -x   # Show which command is being run
 
-# Sets default backend to Agg
-cp tests/matplotlibrc .
-
 # Step 1: pre-install required packages
 if [[ ${dependencies} == "full" || ${dependencies} == "cartopy" ]]; then
     case ${RUNNER_OS} in
     linux|Linux)
         sudo apt-get -qqy update
-        sudo apt-get -qqy install \
-        libhdf5-serial-dev \
-        libnetcdf-dev \
-        libopenmpi-dev \
-        libfuse2
+        sudo apt-get -qqy install libfuse2
         ;;
     osx|macOS)
         sudo mkdir -p /usr/local/man
         sudo chown -R "${USER}:admin" /usr/local/man
-        # uninstalling pkg-config to workaround a bug in macOS image
-        # https://github.com/Homebrew/homebrew-core/pull/198691#issuecomment-2495500991
-        # this can be cleaned-up once the following patch is released:
-        # https://github.com/actions/runner-images/pull/11015
-        HOMEBREW_NO_AUTO_UPDATE=1 brew uninstall pkg-config@0.29.2 || true
-        HOMEBREW_NO_AUTO_UPDATE=1 brew install hdf5 open-mpi netcdf ccache macfuse
+        HOMEBREW_NO_AUTO_UPDATE=1 brew install macfuse
         ;;
     esac
 fi