--- a/stable/CMakeLists.txt
+++ b/stable/CMakeLists.txt
@@ -34,7 +34,9 @@ add_executable ( rom2c EXCLUDE_FROM_ALL
    "${COMMON}/rom2c.c"
    )
 target_link_libraries ( rom2c ${DYNAMIPS_LIBRARIES} )
-set ( ROM2C_EXECUTABLE "${CMAKE_CURRENT_BINARY_DIR}/rom2c${CMAKE_EXECUTABLE_SUFFIX}" CACHE INTERNAL "rom2c executable" )
+if ( NOT ROM2C_EXECUTABLE )
+   set ( ROM2C_EXECUTABLE "${CMAKE_CURRENT_BINARY_DIR}/rom2c${CMAKE_EXECUTABLE_SUFFIX}" CACHE INTERNAL "rom2c executable" )
+endif ( NOT ROM2C_EXECUTABLE )
 
 # mips64_microcode_dump.inc
 set ( _input "${LOCAL}/mips64_microcode" )