diff --git a/cwkey/drivers/CWWinKey.cpp b/cwkey/drivers/CWWinKey.cpp
index 0899bc00..0a4dbdf9 100644
--- a/cwkey/drivers/CWWinKey.cpp
+++ b/cwkey/drivers/CWWinKey.cpp
@@ -93,7 +93,7 @@ bool CWWinKey2::open()
     cmd.resize(3);
     cmd[0] = 0x00;
     cmd[1] = 0x04;
-    cmd[2] = 0xF1;
+    cmd[2] = 0xF1u;
 
     if ( sendDataAndWait(cmd) != 3 )
     {
@@ -627,7 +627,7 @@ bool CWWinKey2::__setPOTRange()
     cmd[0] = 0x05;
     cmd[1] = minWPMRange;
     cmd[2] = 31;
-    cmd[3] = 0xFF;
+    cmd[3] = 0xFFu;
 
     qint64 size = writeAsyncData(cmd);
     if ( size != 4 )