diff --git a/.cirrus.yml b/.cirrus.yml
index 3856f66037..4b65050be3 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -1,16 +1,22 @@
+# since CirrusCI has limited compute resources for free open-source projects
+# we only use it for its unique feature, FreeBSD images
+
 freebsd_instance:
   image_family: freebsd-14-0
 
 task:
+  env:
+    CIRRUS_CLONE_DEPTH: 1
+    CIRRUS_CLONE_SUBMODULES: true
+    CIBW_BUILD_VERBOSITY: 3
+    CIBW_SKIP: pp* cp38-* # cp38-* has problem with x86_64 / arm64 confusion
+    CIBW_BUILD: cp39-* cp310-* cp311-* cp312-*
   install_script: |
-    IGNORE_OSVERSION=yes pkg update
-    pkg install -U -y git boost-build boost-libs unzip wget openssl cmake ninja
+    pkg install -y boost-build boost-libs openssl cmake ninja py39-pip
     echo "using clang ;" > ~/user-config.jam
-  submodules_script: |
-    git submodule update --init --recursive
   build_cmake_script: |
     cmake -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_FLAGS="-Werror" -DCMAKE_CXX_STANDARD=14 -Dbuild_tests=ON -Dbuild_examples=ON -Dbuild_tools=ON -Dpython-bindings=OFF -G Ninja .
-    cmake --build . --parallel 2
+    cmake --build .
     ./test/test_primitives
   tests_script: |
     cd test
@@ -19,79 +25,11 @@ task:
     cd test
     b2 -l250 warnings-as-errors=on warnings=all crypto=openssl stage_enum_if stage_dependencies include=/usr/local/include library-path=/usr/local/lib
     LD_LIBRARY_PATH=./dependencies ./enum_if
+# it appears cibuildwheel does not support FreeBSD (nor CirrusCI)
+#  install_cibuildwheel_script:
+#    - python -m pip install cibuildwheel==2.16.5
+#  run_cibuildwheel_script:
+#    - cibuildwheel
+#  wheels_artifacts:
+#    path: "wheelhouse/*"
 
-build_and_store_wheels: &BUILD_AND_STORE_WHEELS
-  env:
-    CIBW_BUILD_VERBOSITY: 3
-    CIBW_REPAIR_WHEEL_COMMAND_MACOS: >
-      delocate-listdeps {wheel} &&
-      delocate-wheel --require-archs {delocate_archs} -w {dest_dir} -v {wheel}
-
-  install_cibuildwheel_script:
-    - $PYTHON -m pip install cibuildwheel==2.16.5
-
-  run_cibuildwheel_script:
-    - cibuildwheel
-
-  wheels_artifacts:
-    path: "wheelhouse/*"
-
-build_macos_arm64_task:
-  name: Build macOS arm64 wheels.
-
-  macos_instance:
-    image: ghcr.io/cirruslabs/macos-sonoma-xcode:latest
-
-  env:
-    CIRRUS_CLONE_SUBMODULES: true
-    CIBW_SKIP: pp* cp38-* # cp38-* has problem with x86_64 / arm64 confusion
-    CIBW_BUILD: cp39-* cp310-* cp311-* cp312-*
-    CIBW_ARCH: arm64
-    PATH: /opt/homebrew/bin:$PATH
-    PYTHON: python3.9
-
-  install_pre_requirements_script:
-    - brew install python@3.9
-
-  debug_script:
-    - echo $PATH
-    - ls -l /opt/homebrew/bin
-    - find /opt/homebrew -name '*openssl*' -ls
-
-  <<: *BUILD_AND_STORE_WHEELS
-
-test_macos_arm64_task:
-  name: Test macOS arm64.
-
-  macos_instance:
-    image: ghcr.io/cirruslabs/macos-sonoma-xcode:latest
-
-  env:
-    CIRRUS_CLONE_SUBMODULES: true
-    PATH: /opt/homebrew/bin:$PATH
-    PYTHON: python3.9
-    OPENSSL_OPTS: >
-      openssl-lib=/opt/homebrew/opt/openssl@3.0/lib
-      openssl-include=/opt/homebrew/opt/openssl@3.0/include
-
-  install_pre_requirements_script:
-    - brew install python@3.9
-    - brew install boost-build boost openssl@3.0
-    - echo "using darwin ;" >>~/user-config.jam
-
-  debug_script:
-    - echo $PATH
-    - ls -l /opt/homebrew/bin
-    - find /opt/homebrew -name '*openssl*' -ls
-
-  test_script:
-    - cd test
-    - b2 crypto=built-in -l400 warnings-as-errors=on debug-iterators=on invariant-checks=full asserts=on deterministic-tests
-    - b2 $OPENSSL_OPTS crypto=openssl -l400 warnings-as-errors=on debug-iterators=on invariant-checks=full asserts=on deterministic-tests
-    - b2 $OPENSSL_OPTS deprecated-functions=off -l400 warnings-as-errors=on debug-iterators=on invariant-checks=full asserts=on deterministic-tests
-
-  test_flaky_script:
-    - cd test
-    - b2 crypto=built-in -l400 warnings-as-errors=on debug-iterators=on invariant-checks=full asserts=on
-    - b2 $OPENSSL_OPTS crypto=openssl -l400 warnings-as-errors=on debug-iterators=on invariant-checks=full asserts=on
-    - b2 $OPENSSL_OPTS deprecated-functions=off -l400 warnings-as-errors=on debug-iterators=on invariant-checks=full asserts=on