diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 8fc36371..81b98804 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -22,5 +22,7 @@ jobs:
         run: make -C test
       - name: Check if machine.c can be compiled for all machines
         run: make machine_check
-      - name: Make project
-        run: make MACHINE="KP_9000_6XHML_X2"
+      - name: Make project (4x2/RTL8372)
+        run: make CI=1 MACHINE="KP_9000_6XHML_X2"
+      - name: Make project (8x1/RTL8373)
+        run: make CI=1 MACHINE="KP_9000_9XHML_X_V3_1"
diff --git a/Makefile b/Makefile
index 4b0190d2..a35e8da9 100644
--- a/Makefile
+++ b/Makefile
@@ -20,6 +20,10 @@ else
 	CC_FLAGS += -DMACHINE_$(MACHINE)
 endif
 
+ifeq ($(CI),1)
+	CC_FLAGS += --Werror
+endif
+
 BUILDDIR = output/$(MACHINE)
 VERSION_HEADER := version.h