diff --git a/src/core/gcodecommands.cpp b/src/core/gcodecommands.cpp
--- a/src/core/gcodecommands.cpp
+++ b/src/core/gcodecommands.cpp
@@ -102,7 +102,7 @@
     case G0:
     case G1:
     case G28:
-        code = value1.isEmpty() ? code : code.append(QStringLiteral(" %1").arg(value1.toUpper()));
+        code = value1.isEmpty() ? code : code.append(QStringLiteral(" %1").arg(value1));
         return code;
 
     default:
diff --git a/src/widgets/commandwidget.cpp b/src/widgets/commandwidget.cpp
--- a/src/widgets/commandwidget.cpp
+++ b/src/widgets/commandwidget.cpp
@@ -39,6 +39,11 @@
     connect(newButton, &QPushButton::clicked, this, [this] {
         if (!lineCommand->text().isEmpty())
         {
+            if (lineCommand->text().startsWith(QStringLiteral("g"))) {
+                lineCommand->setText(lineCommand->text().replace(0, 1, QStringLiteral("G")));
+            } else if (lineCommand->text().startsWith(QStringLiteral("m"))) {
+                lineCommand->setText(lineCommand->text().replace(0, 1, QStringLiteral("M")));
+            }
             emit commandPressed(lineCommand->text());
             lineCommand->clear();
         }
diff --git a/testclient/mainwindow.cpp b/testclient/mainwindow.cpp
--- a/testclient/mainwindow.cpp
+++ b/testclient/mainwindow.cpp
@@ -129,7 +129,7 @@
     commandWidget = new CommandWidget;
     //Connect the commandPressed signal
     connect(commandWidget, &CommandWidget::commandPressed, [this](const QString & command) {
-        core->pushCommand(command.toUpper());
+        core->pushCommand(command);
     });
     //Connect the messagePressed signal
     connect(commandWidget, &CommandWidget::messagePressed, [this](const QString & message) {