diff --git a/AMSS_NCKU_source/makefile.inc b/AMSS_NCKU_source/makefile.inc
index 331cff1..28146e5 100755
--- a/AMSS_NCKU_source/makefile.inc
+++ b/AMSS_NCKU_source/makefile.inc
@@ -46,12 +46,12 @@ endif
 ## Kernel implementation switch
 ##   1 (default) : use C++ rewrite of bssn_rhs and helper kernels (faster)
 ##   0           : fall back to original Fortran kernels
-USE_CXX_KERNELS ?= 1
+USE_CXX_KERNELS ?= 0
 
 ## RK4 kernel implementation switch
 ##   1 (default) : use C/C++ rewrite of rungekutta4_rout (for optimization experiments)
 ##   0           : use original Fortran rungekutta4_rout.o
-USE_CXX_RK4 ?= 1
+USE_CXX_RK4 ?= 0
 
 f90          = ifx
 f77          = ifx