diff --git a/src/PrusaSlicer.cpp b/src/PrusaSlicer.cpp
index be432d487a..1bd981a5da 100644
--- a/src/PrusaSlicer.cpp
+++ b/src/PrusaSlicer.cpp
@@ -156,7 +156,7 @@ int CLI::run(int argc, char **argv)
 #if ENABLE_GCODE_VIEWER
     for (const std::string& file : m_input_files) {
         std::string ext = boost::filesystem::path(file).extension().string();
-        if (boost::filesystem::path(file).extension().string() == ".gcode") {
+        if (ext == ".gcode" || ext == ".g") {
             if (boost::filesystem::exists(file)) {
                 start_as_gcodeviewer = true;
                 break;
diff --git a/src/slic3r/GUI/Plater.cpp b/src/slic3r/GUI/Plater.cpp
index b3cd1ef000..b62ff4dcc8 100644
--- a/src/slic3r/GUI/Plater.cpp
+++ b/src/slic3r/GUI/Plater.cpp
@@ -4702,7 +4702,9 @@ void Plater::load_gcode()
 
 void Plater::load_gcode(const wxString& filename)
 {
-    if (filename.empty() || m_last_loaded_gcode == filename)
+    if (filename.empty() ||
+        (!filename.Lower().EndsWith(".gcode") && !filename.Lower().EndsWith(".g")) ||
+        m_last_loaded_gcode == filename)
         return;
 
     m_last_loaded_gcode = filename;