diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ecb3b91..71307f0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -75,21 +75,22 @@ jobs:
         if [ -n "${{ matrix.job.toolchain }}" ]; then TOOLCHAIN="${{ matrix.job.toolchain }}" ; fi
         outputs TOOLCHAIN
         # target-specific options
-        # * CARGO_FEATURES_OPTION
-        CARGO_FEATURES_OPTION='--all -- --check' ;  ## default to '--all-features' for code coverage
         # * CODECOV_FLAGS
         CODECOV_FLAGS=$( echo "${{ matrix.job.os }}" | sed 's/[^[:alnum:]]/_/g' )
         outputs CODECOV_FLAGS
 
     - name: rust toolchain ~ install
       uses: dtolnay/rust-toolchain@nightly
+    - name: Install llvm-tools-preview
+      run: rustup component add llvm-tools-preview
     - name: Test
-      run: cargo test ${{ steps.vars.outputs.CARGO_FEATURES_OPTION }} --no-fail-fast
+      run: cargo test --no-fail-fast
       env:
         CARGO_INCREMENTAL: "0"
         RUSTC_WRAPPER: ""
-        RUSTFLAGS: "-Zprofile -Ccodegen-units=1 -Copt-level=0 -Clink-dead-code -Coverflow-checks=off -Zpanic_abort_tests -Cpanic=abort"
+        RUSTFLAGS: "-Cinstrument-coverage -Zcoverage-options=branch -Ccodegen-units=1 -Copt-level=0 -Clink-dead-code -Coverflow-checks=off -Zpanic_abort_tests -Cpanic=abort"
         RUSTDOCFLAGS: "-Cpanic=abort"
+        LLVM_PROFILE_FILE: "bsdutils-%p-%m.profraw"
     - name: "`grcov` ~ install"
       id: build_grcov
       shell: bash
@@ -117,9 +118,9 @@ jobs:
         COVERAGE_REPORT_FILE="${COVERAGE_REPORT_DIR}/lcov.info"
         mkdir -p "${COVERAGE_REPORT_DIR}"
         # display coverage files
-        grcov . --output-type files --ignore build.rs --ignore "vendor/*" --ignore "/*" --ignore "[a-zA-Z]:/*" --excl-br-line "^\s*((debug_)?assert(_eq|_ne)?!|#\[derive\()" | sort --unique
+        grcov . --binary-path="${COVERAGE_REPORT_DIR}" --output-type files --ignore build.rs --ignore "vendor/*" --ignore "/*" --ignore "[a-zA-Z]:/*" --excl-br-line "^\s*((debug_)?assert(_eq|_ne)?!|#\[derive\()" | sort --unique
         # generate coverage report
-        grcov . --output-type lcov --output-path "${COVERAGE_REPORT_FILE}" --branch --ignore build.rs --ignore "vendor/*" --ignore "/*" --ignore "[a-zA-Z]:/*" --excl-br-line "^\s*((debug_)?assert(_eq|_ne)?!|#\[derive\()"
+        grcov . --binary-path="${COVERAGE_REPORT_DIR}" --output-type lcov --output-path "${COVERAGE_REPORT_FILE}" --branch --ignore build.rs --ignore "vendor/*" --ignore "/*" --ignore "[a-zA-Z]:/*" --excl-br-line "^\s*((debug_)?assert(_eq|_ne)?!|#\[derive\()"
         echo "report=${COVERAGE_REPORT_FILE}" >> $GITHUB_OUTPUT
     - name: Upload coverage results (to Codecov.io)
       uses: codecov/codecov-action@v4