diff --git a/ui/build/config.go b/ui/build/config.go
index 6f2d24a..345d8ea 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -50,6 +50,7 @@
 	targetDevice    string
 	targetDeviceDir string
 
+	pdkBuild       bool
 	brokenDupRules bool
 
 	pathReplaced bool
@@ -579,3 +580,11 @@
 func (c *configImpl) TargetDeviceDir() string {
 	return c.targetDeviceDir
 }
+
+func (c *configImpl) SetPdkBuild(pdk bool) {
+	c.pdkBuild = pdk
+}
+
+func (c *configImpl) IsPdkBuild() bool {
+	return c.pdkBuild
+}
diff --git a/ui/build/dumpvars.go b/ui/build/dumpvars.go
index cc9e742..05314cb 100644
--- a/ui/build/dumpvars.go
+++ b/ui/build/dumpvars.go
@@ -187,5 +187,6 @@
 	config.SetTargetDevice(make_vars["TARGET_DEVICE"])
 	config.SetTargetDeviceDir(make_vars["TARGET_DEVICE_DIR"])
 
+	config.SetPdkBuild(make_vars["TARGET_BUILD_PDK"] == "true")
 	config.SetBuildBrokenDupRules(make_vars["BUILD_BROKEN_DUP_RULES"] != "false")
 }
diff --git a/ui/build/kati.go b/ui/build/kati.go
index 743da4a..1494688 100644
--- a/ui/build/kati.go
+++ b/ui/build/kati.go
@@ -83,6 +83,11 @@
 		"-f", "build/make/core/main.mk",
 	}
 
+	// PDK builds still uses a few implicit rules
+	if !config.IsPdkBuild() {
+		args = append(args, "--warn_implicit_rules")
+	}
+
 	if !config.BuildBrokenDupRules() {
 		args = append(args, "--werror_overriding_commands")
 	}