diff --git a/.github/workflows/coq-demo.yml b/.github/workflows/coq-demo.yml
index 5571efb..c3e38c6 100644
--- a/.github/workflows/coq-demo.yml
+++ b/.github/workflows/coq-demo.yml
@@ -228,28 +228,21 @@ jobs:
         with:
           opam_file: 'coq-demo.opam'
           custom_image: ${{ matrix.image }}
-          install: |
-            # don't wait CI time installing
-          before_script: |
+          custom_script: |
             startGroup "Toy example"
-              find "$(dirname "$(dirname "$GITHUB_STEP_SUMMARY")")"
-              ls -la "$(dirname "$(dirname "$GITHUB_STEP_SUMMARY")")"
-              ls -la "$(dirname "$GITHUB_STEP_SUMMARY")"
-              sudo chmod -R a+rw "$(dirname "$GITHUB_STEP_SUMMARY")"
-              ls -la "$(dirname "$GITHUB_STEP_SUMMARY")"
-              ls -la $GITHUB_STEP_SUMMARY || true
-              echo "ex_var=$ex_var" | tee -a $GITHUB_STEP_SUMMARY
-              echo "ex_var_global=$ex_var" | tee -a $GITHUB_ENV
               [ "$ex_var" = "ex_value" ]
+              echo "GITHUB_ENV=$GITHUB_ENV"
+              echo "ex_var_global=$ex_var.final" | tee -a $GITHUB_ENV
             endGroup
-          export: 'ex_var OPAMWITHTEST GITHUB_STEP_SUMMARY'  # space-separated list of variables
+          export: 'ex_var GITHUB_ENV'  # space-separated list of variables
+          # TODO cleanup, redo OPAMWITHTEST
         env:
           OPAMWITHTEST: 'true'
           ex_var: 'ex_value'
       - run: |
           # test persistence of ex_var_global via $GITHUB_ENV
           echo "ex_var_global=$ex_var_global"
-          [ "$ex_var_global" = "ex_value" ]
+          [ "$ex_var_global" = "ex_value.final" ]
 
   # The following two jobs illustrate the installation of system packages.
 
diff --git a/entrypoint.sh b/entrypoint.sh
index e2afaf5..63a62b4 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -25,9 +25,15 @@ echo "GITHUB_REPOSITORY=$GITHUB_REPOSITORY"
 echo "RUNNER_OS=$RUNNER_OS"
 echo "RUNNER_TEMP=$RUNNER_TEMP"
 echo "RUNNER_WORKSPACE=$RUNNER_WORKSPACE"
-# GITHUB_ENV is somewhat arbitrary, all of the file variables should be similar, might be something like /home/runner/work/_temp/_runner_file_commands/set_env_87406d6e-4979-4d42-98e1-3dab1f48b13a or /github/file_commands/set_env_3b186eb5-242d-4edf-b107-b13e98e56988
-DIR_GITHUB_RUNNER_FILE_COMMANDS="$(dirname "$GITHUB_ENV")"
+
+# We want to bind-mount the dirname of $GITHUB_ENV.
+# $GITHUB_ENV is typically /home/runner/work/_temp/_runner_file_commands/set_env_87406d6e-4979-4d42-98e1-3dab1f48b13a
+# so $(dirname "$GITHUB_ENV") is typically /home/runner/work/_temp/_runner_file_commands on the host.
+# We also notice that $RUNNER_WORKSPACE is typically /home/runner/work/${GITHUB_REPOSITORY#*/} (e.g. /home/runner/work/docker-coq-action).
+# Hence this hardcoded yet as-general-as-possible path:
+DIR_GITHUB_RUNNER_FILE_COMMANDS="${RUNNER_WORKSPACE#*/}/_temp/_runner_file_commands"
 echo "DIR_GITHUB_RUNNER_FILE_COMMANDS=$DIR_GITHUB_RUNNER_FILE_COMMANDS"
+
 # Assuming you used https://github.com/actions/checkout,
 # the GITHUB_WORKSPACE variable corresponds to the following host dir:
 # ${RUNNER_WORKSPACE}/${GITHUB_REPOSITORY#*/}, see also
@@ -213,7 +219,7 @@ endGroup
 
 ## Note to docker-coq-action maintainers: Run ./helper.sh gen & Copy min.sh
 # shellcheck disable=SC2046,SC2086
-echorun docker run --pull=never -i --init --rm --name=COQ $( [ -n "$INPUT_EXPORT" ] && printf -- "-e %s " $INPUT_EXPORT ) -e WORKDIR="$WORKDIR" -e PACKAGE="$PACKAGE" \
+docker run --pull=never -i --init --rm --name=COQ $( [ -n "$INPUT_EXPORT" ] && printf -- "-e %s " $INPUT_EXPORT ) -e WORKDIR="$WORKDIR" -e PACKAGE="$PACKAGE" \
        -v "$HOST_WORKSPACE_REPO:$PWD" -w "$PWD" \
        -v "$DIR_GITHUB_RUNNER_FILE_COMMANDS:$DIR_GITHUB_RUNNER_FILE_COMMANDS" \
        "$COQ_IMAGE" /bin/bash --login -c "