diff --git a/src/client/CMakeLists.txt b/src/client/CMakeLists.txt
index 6c8f33f6..f4363bf0 100644
--- a/src/client/CMakeLists.txt
+++ b/src/client/CMakeLists.txt
@@ -104,4 +104,4 @@ set(client_SOURCES ${client_SOURCES}
 )
 
 set_source_files_properties(${CMAKE_CURRENT_LIST_DIR}/luafunctions.cpp
-                            PROPERTIES LANGUAGE CXX COMPILE_FLAGS "-g0 -O0")
+                            PROPERTIES LANGUAGE CXX COMPILE_FLAGS "-g0 -Os")
diff --git a/src/framework/CMakeLists.txt b/src/framework/CMakeLists.txt
index fca595db..aa3e7ed8 100644
--- a/src/framework/CMakeLists.txt
+++ b/src/framework/CMakeLists.txt
@@ -129,7 +129,7 @@ set(framework_SOURCES ${framework_SOURCES}
 )
 
 set_source_files_properties(${CMAKE_CURRENT_LIST_DIR}/luafunctions.cpp
-                            PROPERTIES LANGUAGE CXX COMPILE_FLAGS "-g0 -O0")
+                            PROPERTIES LANGUAGE CXX COMPILE_FLAGS "-g0 -Os")
 
 # some build options
 option(CRASH_HANDLER "Generate crash reports" ON)
diff --git a/src/framework/luaengine/luainterface.cpp b/src/framework/luaengine/luainterface.cpp
index d714d928..230e27b6 100644
--- a/src/framework/luaengine/luainterface.cpp
+++ b/src/framework/luaengine/luainterface.cpp
@@ -902,7 +902,6 @@ void LuaInterface::setEnv(int index)
 {
     assert(hasIndex(index));
     lua_setfenv(L, index);
-    assert(ret == 1);
 }
 
 void LuaInterface::getTable(int index)