diff --git a/bus.cpp b/bus.cpp
index 5aa06a4..b19807c 100644
--- a/bus.cpp
+++ b/bus.cpp
@@ -833,9 +833,12 @@ write_rc_t bus::write(const uint16_t addr_in, const word_mode_t word_mode, uint1
 			return { false };
 		}
 
-		if (a == ADDR_LFC) // line frequency clock and status register
+		if (a == ADDR_LFC) { // line frequency clock and status register
 			kw11_l_->writeWord(a, value);
 
+			return { false };
+		}
+
 		if (tm11 && a >= TM_11_BASE && a < TM_11_END) {
 			DOLOG(debug, false, "WRITE-I/O TM11 register %d: %06o", (a - TM_11_BASE) / 2, value);
 			word_mode == wm_byte ? tm11->writeByte(a, value) : tm11->writeWord(a, value);
diff --git a/kw11-l.cpp b/kw11-l.cpp
index 1661ed0..449bfb2 100644
--- a/kw11-l.cpp
+++ b/kw11-l.cpp
@@ -34,8 +34,11 @@ kw11_l::~kw11_l()
 	stop_flag = true;
 
 #if !defined(ESP32) && !defined(BUILD_FOR_RP2040)
-	th->join();
-	delete th;
+	if (th) {
+		th->join();
+
+		delete th;
+	}
 #endif
 }
 
@@ -62,7 +65,6 @@ void kw11_l::operator()()
 
 	while(!stop_flag) {
 		if (*cnsl->get_running_flag()) {
-			DOLOG(debug, true, "KW11-L tick");
 			set_lf_crs_b7();
  
 			if (get_lf_crs() & 64)
diff --git a/kw11-l.h b/kw11-l.h
index eb423a3..666ac40 100644
--- a/kw11-l.h
+++ b/kw11-l.h
@@ -11,18 +11,18 @@
 class kw11_l
 {
 private:
-	bus         *const b         { nullptr };
-	console           *cnsl      { nullptr };
+	bus         *const b          { nullptr };
+	console           *cnsl       { nullptr };
 
 #if defined(BUILD_FOR_RP2040)
 	SemaphoreHandle_t lf_csr_lock { xSemaphoreCreateBinary() };
 #else
-	std::thread *      th        { nullptr };
-	std::mutex lf_csr_lock;
+	std::thread       *th         { nullptr };
+	std::mutex         lf_csr_lock;
 #endif
-	uint16_t   lf_csr { 0 };
+	uint16_t           lf_csr     { 0       };
 
-	std::atomic_bool   stop_flag { false };
+	std::atomic_bool   stop_flag  { false   };
 
 	uint8_t  get_lf_crs();
 	void     set_lf_crs_b7();