diff --git a/components/bootloader/project_include.cmake b/components/bootloader/project_include.cmake
index cdb18a9fa..4b0137e94 100644
--- a/components/bootloader/project_include.cmake
+++ b/components/bootloader/project_include.cmake
@@ -15,9 +15,10 @@ set(bootloader_binary_files
 
 externalproject_add(bootloader
     # TODO: support overriding the bootloader in COMPONENT_PATHS
-    SOURCE_DIR "${IDF_PATH}/components/bootloader/subproject"
+    SOURCE_DIR "${CMAKE_CURRENT_LIST_DIR}/subproject"
     BINARY_DIR "${bootloader_build_dir}"
-    CMAKE_ARGS -DSDKCONFIG=${SDKCONFIG} -DIDF_PATH=${IDF_PATH}
+    CMAKE_ARGS  -DSDKCONFIG=${SDKCONFIG} -DIDF_PATH=${IDF_PATH}
+                -DEXTRA_COMPONENT_DIRS=${CMAKE_CURRENT_LIST_DIR}
     INSTALL_COMMAND ""
     BUILD_ALWAYS 1  # no easy way around this...
     BUILD_BYPRODUCTS ${bootloader_binary_files}
diff --git a/tools/ci/test_build_system_cmake.sh b/tools/ci/test_build_system_cmake.sh
index c679acc5c..5c434ab34 100755
--- a/tools/ci/test_build_system_cmake.sh
+++ b/tools/ci/test_build_system_cmake.sh
@@ -238,16 +238,13 @@ EOF
     export PATH="$OLDPATH"
     rm ./python
 
-    print_status "sdkconfig should have contents both files: sdkconfig and sdkconfig.defaults"
-    idf.py clean > /dev/null;
-    idf.py fullclean > /dev/null;
-    rm -f sdkconfig.defaults;
-    rm -f sdkconfig;
-    echo "CONFIG_PARTITION_TABLE_OFFSET=0x10000" >> sdkconfig.defaults;
-    echo "CONFIG_PARTITION_TABLE_TWO_OTA=y" >> sdkconfig;
-    idf.py reconfigure > /dev/null;
-    grep "CONFIG_PARTITION_TABLE_OFFSET=0x10000" sdkconfig || failure "The define from sdkconfig.defaults should be into sdkconfig"
-    grep "CONFIG_PARTITION_TABLE_TWO_OTA=y" sdkconfig || failure "The define from sdkconfig should be into sdkconfig"
+    print_status "Custom bootloader overrides original"
+    clean_build_dir
+    (mkdir components && cd components && cp -r $IDF_PATH/components/bootloader .)
+    idf.py build
+    grep "$PWD/components/bootloader/subproject/main/bootloader_start.c" build/bootloader/compile_commands.json \
+        || failure "Custom bootloader source files should be built instead of the original's"
+    rm -rf components
 
     print_status "All tests completed"
     if [ -n "${FAILURES}" ]; then