diff --git a/driver/opae/vlsim/Makefile b/driver/opae/vlsim/Makefile
index b84c24f4..58d2fcd4 100644
--- a/driver/opae/vlsim/Makefile
+++ b/driver/opae/vlsim/Makefile
@@ -1,8 +1,7 @@
 CFLAGS += -std=c++11 -O2 -Wall -Wextra -Wfatal-errors
 #CFLAGS += -std=c++11 -g -O0 -Wall -Wextra -Wfatal-errors
 
-CFLAGS += -Wno-aligned-new -Wno-maybe-uninitialized
-
+CFLAGS += -DUSE_VLSIM -fPIC -Wno-maybe-uninitialized
 CFLAGS += -I../../../../hw
 
 # control RTL debug print states
@@ -21,15 +20,9 @@ DBG_PRINT_FLAGS += -DDBG_PRINT_SCOPE
 DBG_FLAGS += $(DBG_PRINT_FLAGS)
 DBG_FLAGS += -DDBG_CACHE_REQ_INFO
 
-#CONFIGS := -DNUM_CLUSTERS=2 -DNUM_CORES=4 -DL2_ENABLE=1 $(CONFIGS)
-#CONFIGS := -DNUM_CLUSTERS=1 -DNUM_CORES=4 -DL2_ENABLE=1 $(CONFIGS)
-#CONFIGS := -DNUM_CLUSTERS=1 -DNUM_CORES=2 -DL2_ENABLE=0 $(CONFIGS)
-CONFIGS := -DNUM_CLUSTERS=1 -DNUM_CORES=1 $(CONFIGS)
-
-CFLAGS += -fPIC
-
-CFLAGS += -DUSE_VLSIM $(CONFIGS)
+CONFIGS ?= -DNUM_CLUSTERS=1 -DNUM_CORES=1
 
+CFLAGS += $(CONFIGS)
 CFLAGS += -DDUMP_PERF_STATS
 
 LDFLAGS += -shared -pthread
diff --git a/driver/rtlsim/Makefile b/driver/rtlsim/Makefile
index b3d466f7..76e7185d 100644
--- a/driver/rtlsim/Makefile
+++ b/driver/rtlsim/Makefile
@@ -1,7 +1,7 @@
 CFLAGS += -std=c++11 -O2 -Wall -Wextra -Wfatal-errors
 #CFLAGS += -std=c++11 -g -O0 -Wall -Wextra -Wfatal-errors
 
-CFLAGS += -fPIC -Wno-aligned-new -Wno-maybe-uninitialized
+CFLAGS += -DUSE_RTLSIM -fPIC -Wno-maybe-uninitialized
 CFLAGS += -I../../include -I../../../hw/simulate -I../../../hw
 
 # control RTL debug print states
@@ -20,13 +20,9 @@ DBG_PRINT_FLAGS += -DDBG_PRINT_SCOPE
 DBG_FLAGS += $(DBG_PRINT_FLAGS)
 DBG_FLAGS += -DDBG_CACHE_REQ_INFO
 
-#CONFIGS := -DNUM_CLUSTERS=2 -DNUM_CORES=4 -DL2_ENABLE=1 $(CONFIGS)
-#CONFIGS := -DNUM_CLUSTERS=1 -DNUM_CORES=4 -DL2_ENABLE=1 $(CONFIGS)
-#CONFIGS := -DNUM_CLUSTERS=1 -DNUM_CORES=2 -DL2_ENABLE=0 $(CONFIGS)
-CONFIGS := -DNUM_CLUSTERS=1 -DNUM_CORES=1 $(CONFIGS)
+CONFIGS ?= -DNUM_CLUSTERS=1 -DNUM_CORES=1
 
 CFLAGS += $(CONFIGS)
-
 CFLAGS += -DDUMP_PERF_STATS
 
 LDFLAGS += -shared -pthread
diff --git a/driver/simx/Makefile b/driver/simx/Makefile
index 2779145a..154404d0 100644
--- a/driver/simx/Makefile
+++ b/driver/simx/Makefile
@@ -6,16 +6,13 @@ SIMX_DIR = ../../simX
 CXXFLAGS += -std=c++11 -O2 -Wall -Wextra -Wfatal-errors 
 #CXXFLAGS += -std=c++11 -g -O0 -Wall -Wextra -Wfatal-errors
 
-CXXFLAGS += -fPIC -Wno-aligned-new -Wno-maybe-uninitialized
+CXXFLAGS += -DUSE_SIMX -fPIC -Wno-maybe-uninitialized
 CXXFLAGS += -I../include -I../../hw -I$(SIMX_DIR)
-CXXFLAGS += -DDUMP_PERF_STATS
 
-#CONFIGS := -DNUM_CLUSTERS=2 -DNUM_CORES=4 -DL2_ENABLE=1 $(CONFIGS)
-#CONFIGS := -DNUM_CLUSTERS=1 -DNUM_CORES=4 -DL2_ENABLE=1 $(CONFIGS)
-#CONFIGS := -DNUM_CLUSTERS=1 -DNUM_CORES=2 -DL2_ENABLE=0 $(CONFIGS)
-CONFIGS := -DNUM_CLUSTERS=1 -DNUM_CORES=1 $(CONFIGS)
+CONFIGS ?= -DNUM_CLUSTERS=1 -DNUM_CORES=1
 
 CXXFLAGS += $(CONFIGS)
+CXXFLAGS += -DDUMP_PERF_STATS
 
 LDFLAGS += -shared -pthread
 #LDFLAGS += -dynamiclib -pthread
diff --git a/hw/simulate/Makefile b/hw/simulate/Makefile
index 192be90d..e5856b4b 100644
--- a/hw/simulate/Makefile
+++ b/hw/simulate/Makefile
@@ -1,7 +1,7 @@
 CFLAGS += -std=c++11 -O2 -Wall -Wextra -Wfatal-errors
 #CFLAGS += -std=c++11 -g -O0 -Wall -Wextra -Wfatal-errors
 
-CFLAGS += -Wno-aligned-new -Wno-maybe-uninitialized
+CFLAGS += -Wno-maybe-uninitialized
 
 CFLAGS += -I../..
 
diff --git a/simX/Makefile b/simX/Makefile
index 76fc6e7e..cc443f6a 100644
--- a/simX/Makefile
+++ b/simX/Makefile
@@ -1,12 +1,10 @@
 #CXXFLAGS += -std=c++11 -O2 -Wall -Wextra -Wfatal-errors 
 CXXFLAGS += -std=c++11 -g -O0 -Wall -Wextra -Wfatal-errors
 
-CXXFLAGS += -Wno-aligned-new -Wno-maybe-uninitialized
+CXXFLAGS += -Wno-maybe-uninitialized
 CXXFLAGS += -I. -I../hw
 CXXFLAGS += -DDUMP_PERF_STATS
 
-LDFLAGS +=
-
 TOP = vx_cache_sim
 
 RTL_DIR = ../hw/rtl