diff --git a/tests/hwsim/build.sh b/tests/hwsim/build.sh
index 042af7532..a65ff593e 100755
--- a/tests/hwsim/build.sh
+++ b/tests/hwsim/build.sh
@@ -5,11 +5,15 @@ set -e
 cd $(dirname $0)
 
 cd ../../wpa_supplicant
-cp ../tests/hwsim/example-wpa_supplicant.config .config
+if [ ! -e .config ]; then
+    cp ../tests/hwsim/example-wpa_supplicant.config .config
+fi
 make clean
 make -j8
 cd ../hostapd
-cp ../tests/hwsim/example-hostapd.config .config
+if [ ! -e .config ]; then
+    cp ../tests/hwsim/example-hostapd.config .config
+fi
 make clean
 make -j8 hostapd hlr_auc_gw
 cd ../wlantest