diff --git a/client/cmdlfem4x.c b/client/cmdlfem4x.c
index 47a05b260..f9ebf5f03 100644
--- a/client/cmdlfem4x.c
+++ b/client/cmdlfem4x.c
@@ -206,11 +206,11 @@ void ConstructEM410xEmulGraph(const char *uid,const  uint8_t clock) {
 	int i, j, binary[4], parity[4];
 	uint32_t n;
 	/* clear our graph */
-	ClearGraph(0);
+	ClearGraph(false);
 
 	/* write 9 start bits */
 	for (i = 0; i < 9; i++)
-		AppendGraph(0, clock, 1);
+		AppendGraph(false, clock, 1);
 
 	/* for each hex char */
 	parity[0] = parity[1] = parity[2] = parity[3] = 0;
@@ -221,13 +221,13 @@ void ConstructEM410xEmulGraph(const char *uid,const  uint8_t clock) {
 			binary[j] = n % 2;
 
 		/* append each bit */
-		AppendGraph(0, clock, binary[0]);
-		AppendGraph(0, clock, binary[1]);
-		AppendGraph(0, clock, binary[2]);
-		AppendGraph(0, clock, binary[3]);
+		AppendGraph(false, clock, binary[0]);
+		AppendGraph(false, clock, binary[1]);
+		AppendGraph(false, clock, binary[2]);
+		AppendGraph(false, clock, binary[3]);
 
 		/* append parity bit */
-		AppendGraph(0, clock, binary[0] ^ binary[1] ^ binary[2] ^ binary[3]);
+		AppendGraph(false, clock, binary[0] ^ binary[1] ^ binary[2] ^ binary[3]);
 
 		/* keep track of column parity */
 		parity[0] ^= binary[0];
@@ -237,13 +237,13 @@ void ConstructEM410xEmulGraph(const char *uid,const  uint8_t clock) {
 	}
 
 	/* parity columns */
-	AppendGraph(0, clock, parity[0]);
-	AppendGraph(0, clock, parity[1]);
-	AppendGraph(0, clock, parity[2]);
-	AppendGraph(0, clock, parity[3]);
+	AppendGraph(false, clock, parity[0]);
+	AppendGraph(false, clock, parity[1]);
+	AppendGraph(false, clock, parity[2]);
+	AppendGraph(false, clock, parity[3]);
 
 	/* stop bit */
-	AppendGraph(1, clock, 0);
+	AppendGraph(true, clock, 0);
 }
 
 //by marshmellow
diff --git a/client/graph.c b/client/graph.c
index 0f7789093..c3f6a2b99 100644
--- a/client/graph.c
+++ b/client/graph.c
@@ -13,8 +13,10 @@ int GraphBuffer[MAX_GRAPH_TRACE_LEN];
 int GraphTraceLen;
 int s_Buff[MAX_GRAPH_TRACE_LEN];
 
-/* write a manchester bit to the graph */
-void AppendGraph(int redraw, int clock, int bit) {
+/* write a manchester bit to the graph
+TODO,  verfy that this doesn't overflow buffer  (iceman)
+*/
+void AppendGraph(bool redraw, int clock, int bit) {
 	int i;
 	//set first half the clock bit (all 1's or 0's for a 0 or 1 bit)
 	for (i = 0; i < (int)(clock / 2); ++i)
@@ -28,7 +30,7 @@ void AppendGraph(int redraw, int clock, int bit) {
 }
 
 // clear out our graph window
-int ClearGraph(int redraw) {
+int ClearGraph(bool redraw) {
 	int gtl = GraphTraceLen;
 	memset(GraphBuffer, 0x00, GraphTraceLen);
 	GraphTraceLen = 0;
@@ -60,7 +62,7 @@ void save_restoreGB(uint8_t saveOpt) {
 void setGraphBuf(uint8_t *buf, size_t size) {
 	if ( buf == NULL ) return;
 
-	ClearGraph(0);
+	ClearGraph(false);
 
 	if ( size > MAX_GRAPH_TRACE_LEN )
 		size = MAX_GRAPH_TRACE_LEN;
diff --git a/client/graph.h b/client/graph.h
index 3e56d09f2..05750ab16 100644
--- a/client/graph.h
+++ b/client/graph.h
@@ -18,8 +18,8 @@
 #include "lfdemod.h"
 #include "cmddata.h" //for g_debugmode
 
-void AppendGraph(int redraw, int clock, int bit);
-int ClearGraph(int redraw);
+void AppendGraph(bool redraw, int clock, int bit);
+int ClearGraph(bool redraw);
 size_t getFromGraphBuf(uint8_t *buff);
 int GetAskClock(const char *str, bool printAns);
 int GetPskClock(const char *str, bool printAns);