diff --git a/tests/psa-client-server/psasim/Makefile b/tests/psa-client-server/psasim/Makefile
index 02b639f..ec6691f 100644
--- a/tests/psa-client-server/psasim/Makefile
+++ b/tests/psa-client-server/psasim/Makefile
@@ -1,11 +1,11 @@
 CFLAGS += -Wall -Werror -std=c99 -D_XOPEN_SOURCE=1 -D_POSIX_C_SOURCE=200809L
 
 ifeq ($(DEBUG),1)
-CFLAGS += -DDEBUG -O0 -g
+override CFLAGS += -DDEBUG -O0 -g
 endif
 
-LIBPSACLIENT := -Llibpsaclient/ -lmbedcrypto -lmbedx509 -lmbedtls
-LIBPSASERVER := -Llibpsaserver/ -lmbedcrypto
+CLIENT_LIBS := -Lclient_libs -lpsaclient -lmbedtls -lmbedx509 -lmbedcrypto
+SERVER_LIBS := -Lserver_libs -lmbedcrypto
 
 MBEDTLS_ROOT_PATH = ../../..
 COMMON_INCLUDE := -I./include -I$(MBEDTLS_ROOT_PATH)/include \
@@ -16,13 +16,14 @@
 					include/psa_manifest/pid.h \
 					include/psa_manifest/sid.h
 
-PSA_CLIENT_COMMON_SRC = src/psa_ff_client.c \
-		 src/psa_sim_crypto_client.c \
-		 src/psa_sim_serialise.c
+LIBPSACLIENT_SRC = src/psa_ff_client.c \
+		 		src/psa_sim_crypto_client.c \
+		 		src/psa_sim_serialise.c
+LIBPSACLIENT_OBJS=$(LIBPSACLIENT_SRC:.c=.o)
 
-PSA_CLIENT_BASE_SRC = $(PSA_CLIENT_COMMON_SRC) src/client.c
+PSA_CLIENT_BASE_SRC = $(LIBPSACLIENT_SRC) src/client.c
 
-PSA_CLIENT_FULL_SRC = $(PSA_CLIENT_COMMON_SRC) \
+PSA_CLIENT_FULL_SRC = $(LIBPSACLIENT_SRC) \
 				$(wildcard src/aut_*.c)
 
 PARTITION_SERVER_BOOTSTRAP = src/psa_ff_bootstrap_TEST_PARTITION.c
@@ -32,21 +33,28 @@
 				 src/psa_sim_crypto_server.c \
 				 src/psa_sim_serialise.c
 
-.PHONY: all clean libpsaclient libpsaserver
+.PHONY: all clean client_libs server_libs
 
 all:
 
 test/seedfile:
 	dd if=/dev/urandom of=./test/seedfile bs=64 count=1
 
-test/psa_client_base: $(PSA_CLIENT_BASE_SRC) $(GENERATED_H_FILES)
-	$(CC) $(COMMON_INCLUDE) $(CFLAGS) $(PSA_CLIENT_BASE_SRC) $(LIBPSACLIENT) $(LDFLAGS) -o $@
+src/%.o: src/%.c $(GENERATED_H_FILES)
+	$(CC) $(COMMON_INCLUDE) $(CFLAGS) -c $< $(LDFLAGS) -o $@
 
-test/psa_client_full: $(PSA_CLIENT_FULL_SRC) $(GENERATED_H_FILES)
-	$(CC) $(COMMON_INCLUDE) $(CFLAGS) $(PSA_CLIENT_FULL_SRC) $(LIBPSACLIENT) $(LDFLAGS) -o $@
+client_libs/libpsaclient: $(LIBPSACLIENT_OBJS)
+	mkdir -p client_libs
+	$(AR) -src client_libs/libpsaclient.a $(LIBPSACLIENT_OBJS)
 
-test/psa_partition: $(PSA_SERVER_SRC) $(GENERATED_H_FILES) test/seedfile
-	$(CC) $(COMMON_INCLUDE) $(CFLAGS) $(PSA_SERVER_SRC) $(LIBPSASERVER) $(LDFLAGS) -o $@
+test/psa_client_base: $(PSA_CLIENT_BASE_SRC) $(GENERATED_H_FILES) test/seedfile
+	$(CC) $(COMMON_INCLUDE) $(CFLAGS) $(PSA_CLIENT_BASE_SRC) $(CLIENT_LIBS) $(LDFLAGS) -o $@
+
+test/psa_client_full: $(PSA_CLIENT_FULL_SRC) $(GENERATED_H_FILES) test/seedfile
+	$(CC) $(COMMON_INCLUDE) $(CFLAGS) $(PSA_CLIENT_FULL_SRC) $(CLIENT_LIBS) $(LDFLAGS) -o $@
+
+test/psa_server: $(PSA_SERVER_SRC) $(GENERATED_H_FILES)
+	$(CC) $(COMMON_INCLUDE) $(CFLAGS) $(PSA_SERVER_SRC) $(SERVER_LIBS) $(LDFLAGS) -o $@
 
 $(PARTITION_SERVER_BOOTSTRAP) $(GENERATED_H_FILES): src/manifest.json src/server.c
 	tools/psa_autogen.py src/manifest.json
@@ -56,17 +64,18 @@
 #
 # Note: these rules assume that mbedtls_config.h is already configured by all.sh.
 # If not using all.sh then the user must do it manually.
-libpsaclient libpsaserver:
+client_libs: client_libs/libpsaclient
+client_libs server_libs:
 	$(MAKE) -C $(MBEDTLS_ROOT_PATH)/library CFLAGS="$(CFLAGS)" LDFLAGS="$(LDFLAGS)" libmbedcrypto.a libmbedx509.a libmbedtls.a
 	mkdir -p $@
 	cp $(MBEDTLS_ROOT_PATH)/library/libmbed*.a $@/
-	$(MAKE) -C $(MBEDTLS_ROOT_PATH) clean
 
-clean:
-	rm -f test/psa_client_base test/psa_client_full test/psa_partition
+clean_server_intermediate_files:
 	rm -f $(PARTITION_SERVER_BOOTSTRAP)
-	rm -rf libpsaclient libpsaserver
 	rm -rf include/psa_manifest
-	rm -f test/psa_service_* test/psa_notify_*
-	rm -f test/*.log
+
+clean: clean_server_intermediate_files
+	rm -f test/psa_client_base test/psa_client_full test/psa_server
+	rm -rf client_libs server_libs
+	rm -f test/psa_service_* test/psa_notify_* test/*.log
 	rm -f test/seedfile