diff --git a/reactos/cmake/CMakeMacros.cmake b/reactos/cmake/CMakeMacros.cmake
index 783c3f5c799..782671d8427 100644
--- a/reactos/cmake/CMakeMacros.cmake
+++ b/reactos/cmake/CMakeMacros.cmake
@@ -154,11 +154,13 @@ function(add_cd_file)
         else()
             #add it in reactos.cab
             dir_to_num(${_CD_DESTINATION} _num)
+            file(RELATIVE_PATH __relative_file ${REACTOS_SOURCE_DIR} ${_CD_FILE})
             if(CMAKE_HOST_SYSTEM_NAME MATCHES Windows)
-                file(APPEND ${REACTOS_BINARY_DIR}/boot/bootdata/packages/reactos.dff.dyn "${_CD_FILE} ${_num}\n")
+                file(APPEND ${REACTOS_BINARY_DIR}/boot/bootdata/packages/reactos.dff.dyn "${__relative_file} ${_num}\n")
             else()
-                file(APPEND ${REACTOS_BINARY_DIR}/boot/bootdata/packages/reactos.dff.dyn "\"${_CD_FILE}\" ${_num}\n")
+                file(APPEND ${REACTOS_BINARY_DIR}/boot/bootdata/packages/reactos.dff.dyn "\"${__relative_file}\" ${_num}\n")
             endif()
+            unset(__relative_file)
             if(_CD_TARGET)
                 #manage dependency
                 add_dependencies(reactos_cab ${_CD_TARGET})