diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d43108aa..7ce0a76b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -216,7 +216,7 @@ jobs:
           name: source-gem
           path: gems
       - run: ./bin/test-gem-install gems -- --${{ matrix.syslib }}-system-libraries ${{ matrix.compile_flags }}
-        shell: bash
+        shell: sh
 
   build_native_gem:
     needs: native_setup
@@ -339,7 +339,7 @@ jobs:
           name: cruby-${{ matrix.platform }}-gem
           path: gems
       - run: ./bin/test-gem-install gems
-        shell: bash
+        shell: sh
 
   cruby-x86_64-linux-musl-install:
     needs: build_native_gem
@@ -363,7 +363,7 @@ jobs:
         with:
           name: cruby-x86_64-linux-gem
           path: gems
-      - run: apk add bash build-base
+      - run: apk add build-base
       - if: matrix.ruby == '3.0' # https://github.com/rake-compiler/rake-compiler/pull/236
         run: gem update --system
       - run: ./bin/test-gem-install ./gems
diff --git a/bin/test-gem-install b/bin/test-gem-install
index bc5c47ad..e22b2915 100755
--- a/bin/test-gem-install
+++ b/bin/test-gem-install
@@ -1,4 +1,4 @@
-#! /usr/bin/env bash
+#! /usr/bin/env sh
 #
 #  run as part of CI
 #
@@ -15,14 +15,14 @@ test -e /etc/os-release && cat /etc/os-release
 
 set -e -x -u
 
-pushd $GEMS_DIR
+cd $GEMS_DIR
 
   gemfile=$(ls *.gem | head -n1)
   ls -l ${gemfile}
   gem install --no-document ${gemfile} -- ${INSTALL_FLAGS}
   gem list -d sqlite3
 
-popd
+cd ..
 
 bundle install --local || bundle install