diff --git a/Makefrag b/Makefrag
index c6ec4e66..57767e9f 100644
--- a/Makefrag
+++ b/Makefrag
@@ -1,5 +1,3 @@
--include $(generated_dir)/Makefrag
-
 # check RISCV environment variable
 ifndef RISCV
 $(error Please set environment variable RISCV. Please take a look at README)
diff --git a/fsim/Makefile b/fsim/Makefile
index ad8ab8e0..4540fa74 100644
--- a/fsim/Makefile
+++ b/fsim/Makefile
@@ -20,6 +20,7 @@ CONFIG ?= DefaultFPGAConfig
 
 include $(base_dir)/Makefrag
 include $(sim_dir)/Makefrag
+-include $(generated_dir)/Makefrag
 include $(base_dir)/vsim/Makefrag-sim
 
 all: $(simv)
diff --git a/vsim/Makefile b/vsim/Makefile
index c15e704d..0dff8b97 100644
--- a/vsim/Makefile
+++ b/vsim/Makefile
@@ -20,6 +20,7 @@ CONFIG ?= DefaultVLSIConfig
 
 include $(base_dir)/Makefrag
 include $(sim_dir)/Makefrag
+-include $(generated_dir)/Makefrag
 include $(base_dir)/vsim/Makefrag-sim
 
 all: $(simv)