diff --git a/top/x300/dev_config.json b/top/x300/dev_config.json
index eb6ce9d..a2eccf7 100644
--- a/top/x300/dev_config.json
+++ b/top/x300/dev_config.json
@@ -1,3 +1,8 @@
 {
-    "warning": { "ignore": ["."]}
+    "warning": { "ignore": ["."]},
+    "critical warning": {
+        "ignore": [
+            "tempmon.v' already exists"
+        ]
+    }
 }
diff --git a/top/x300/ip/ddr3_32bit/Makefile.inc b/top/x300/ip/ddr3_32bit/Makefile.inc
index 5df2f52..04d375c 100644
--- a/top/x300/ip/ddr3_32bit/Makefile.inc
+++ b/top/x300/ip/ddr3_32bit/Makefile.inc
@@ -4,6 +4,8 @@
 
 include $(TOOLS_DIR)/make/viv_ip_builder.mak
 
+# Including mig_7series_v4_2_tempmon.v will cause a critical warning, but leaving
+# it out will cause the build to fail.
 IP_DDR3_32BIT_SRCS = \
 $(IP_BUILD_DIR)/ddr3_32bit/ddr3_32bit.xci \
 $(IP_BUILD_DIR)/ddr3_32bit/ddr3_32bit/user_design/rtl/clocking/mig_7series_v4_2_tempmon.v