diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index b70a275..ef15e94 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -8,7 +8,10 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-22.04, ubuntu-24.04]
+    runs-on: ${{ matrix.os }}
 
     steps:
       - uses: actions/checkout@v3
@@ -19,13 +22,13 @@ jobs:
           sudo apt-get install -y cmake build-essential libgtest-dev lcov
 
       - name: Configure & build (with coverage)
-        run: cmake -S . -B build \
+        run: |
+          cmake -S . -B build \
           -DENABLE_COVERAGE=ON \
           -DBUILD_TESTING=ON \
           -DCMAKE_BUILD_TYPE=Debug
 
-      - name: Build
-        run: cmake --build build --parallel
+          cmake --build build --parallel
 
       - name: Zero coverage counters
         run: lcov -d build -z
@@ -34,10 +37,10 @@ jobs:
         run: ctest --test-dir build --output-on-failure
 
       - name: Capture coverage
-        run: lcov -d build -c -o coverage.info
+        run: lcov -c -d build/CMakeFiles/capancdt_proximity_sensor_lib.dir/src -o coverage.info
 
       - name: Filter coverage
-        run: lcov -r coverage.info '/usr/*' '*/test/*' -o coverage.filtered.info
+        run: lcov --ignore-errors unused -r coverage.info '/usr/*' '*/test/*' -o coverage.filtered.info
 
       - name: Generate HTML report
         run: genhtml coverage.filtered.info --output-directory coverage-report
@@ -45,7 +48,7 @@ jobs:
       - name: Upload coverage-report
         uses: actions/upload-artifact@v4
         with:
-          name: coverage-report
+          name: coverage-report-${{ matrix.os }}
           path: coverage-report
 
       - name: Upload coverage reports to Codecov
diff --git a/CMakeLists.txt b/CMakeLists.txt
index a3565ad..18ceb5a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,12 +3,11 @@ project(capancdt_proximity_sensor_lib LANGUAGES CXX)
 
 option(ENABLE_COVERAGE "Enable coverage reporting" OFF)
 if(ENABLE_COVERAGE)
-message(STATUS "Building with coverage support")
-# GCC/Clang coverage instrumentation
-set(CMAKE_CXX_FLAGS        "${CMAKE_CXX_FLAGS}        --coverage -O0 -g")
-set(CMAKE_C_FLAGS          "${CMAKE_C_FLAGS}          --coverage -O0 -g")
-set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} --coverage")
-set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} --coverage")
+  message(STATUS "Building with coverage instrumentation")
+  set(COVERAGE_FLAGS "--coverage -O0 -g")
+  set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS} ${COVERAGE_FLAGS}")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${COVERAGE_FLAGS}")
+  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} --coverage")
 endif()
 
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
diff --git a/README.md b/README.md
index 5d846ce..609cb53 100644
--- a/README.md
+++ b/README.md
@@ -188,6 +188,15 @@ Install GTest and lcov for testing. On ubuntu you can do this with:
 sudo apt-get install libgtest-dev lcov
 ```
 
+You may need to build GTest:
+
+```bash
+cd /usr/src/googletest
+sudo cmake .
+sudo make
+sudo make install
+```
+
 Build the project:
 
 ```bash