diff --git a/src/Config.h b/src/Config.h
index 25d1ee2c..88eb202a 100644
--- a/src/Config.h
+++ b/src/Config.h
@@ -30,7 +30,7 @@ typedef struct
     int Type;
     void* Value;
     int DefaultInt;
-    char* DefaultStr;
+    const char* DefaultStr;
     int StrLength; // should be set to actual array length minus one
 
 } ConfigEntry;
diff --git a/src/SPI.cpp b/src/SPI.cpp
index 6224338e..e550abd9 100644
--- a/src/SPI.cpp
+++ b/src/SPI.cpp
@@ -129,7 +129,7 @@ void Reset()
     fclose(f);
 
     // take a backup
-    char* firmbkp = "firmware.bin.bak";
+    const char* firmbkp = "firmware.bin.bak";
     f = fopen(firmbkp, "rb");
     if (f) fclose(f);
     else
diff --git a/src/Savestate.cpp b/src/Savestate.cpp
index b58d7acc..97fce93e 100644
--- a/src/Savestate.cpp
+++ b/src/Savestate.cpp
@@ -47,9 +47,9 @@
     * different minor means adjustments may have to be made
 */
 
-Savestate::Savestate(char* filename, bool save)
+Savestate::Savestate(const char* filename, bool save)
 {
-    char* magic = "MELN";
+    const char* magic = "MELN";
 
     Error = false;
 
@@ -153,7 +153,7 @@ Savestate::~Savestate()
     if (file) fclose(file);
 }
 
-void Savestate::Section(char* magic)
+void Savestate::Section(const char* magic)
 {
     if (Error) return;
 
diff --git a/src/Savestate.h b/src/Savestate.h
index 136b0cd0..bb12089b 100644
--- a/src/Savestate.h
+++ b/src/Savestate.h
@@ -28,7 +28,7 @@
 class Savestate
 {
 public:
-    Savestate(char* filename, bool save);
+    Savestate(const char* filename, bool save);
     ~Savestate();
 
     bool Error;
@@ -39,7 +39,7 @@ public:
 
     u32 CurSection;
 
-    void Section(char* magic);
+    void Section(const char* magic);
 
     void Var8(u8* var);
     void Var16(u16* var);
diff --git a/src/libui_sdl/libui/darwin/stddialogs.m b/src/libui_sdl/libui/darwin/stddialogs.m
index 42cb94c0..c8260351 100644
--- a/src/libui_sdl/libui/darwin/stddialogs.m
+++ b/src/libui_sdl/libui/darwin/stddialogs.m
@@ -32,7 +32,7 @@ static char *runSavePanel(NSWindow *parent, NSSavePanel *s)
 	return filename;
 }
 
-char *uiOpenFile(uiWindow *parent, char* filter, char* initpath)
+char *uiOpenFile(uiWindow *parent, const char* filter, const char* initpath)
 {
 	NSOpenPanel *o;
 
@@ -46,7 +46,7 @@ char *uiOpenFile(uiWindow *parent, char* filter, char* initpath)
 	return runSavePanel(windowWindow(parent), o);
 }
 
-char *uiSaveFile(uiWindow *parent, char* filter, char* initpath)
+char *uiSaveFile(uiWindow *parent, const char* filter, const char* initpath)
 {
 	NSSavePanel *s;
 
diff --git a/src/libui_sdl/libui/ui.h b/src/libui_sdl/libui/ui.h
index b100c084..5f40aff3 100644
--- a/src/libui_sdl/libui/ui.h
+++ b/src/libui_sdl/libui/ui.h
@@ -283,8 +283,8 @@ _UI_EXTERN uiMenuItem *uiMenuAppendSubmenu(uiMenu *m, uiMenu* child);
 _UI_EXTERN void uiMenuAppendSeparator(uiMenu *m);
 _UI_EXTERN uiMenu *uiNewMenu(const char *name);
 
-_UI_EXTERN char *uiOpenFile(uiWindow *parent, char* filter, char* initpath);
-_UI_EXTERN char *uiSaveFile(uiWindow *parent, char* filter, char* initpath);
+_UI_EXTERN char *uiOpenFile(uiWindow *parent, const char* filter, const char* initpath);
+_UI_EXTERN char *uiSaveFile(uiWindow *parent, const char* filter, const char* initpath);
 _UI_EXTERN void uiMsgBox(uiWindow *parent, const char *title, const char *description);
 _UI_EXTERN void uiMsgBoxError(uiWindow *parent, const char *title, const char *description);
 
diff --git a/src/libui_sdl/libui/unix/draw.c b/src/libui_sdl/libui/unix/draw.c
index 72d42029..e55397e6 100644
--- a/src/libui_sdl/libui/unix/draw.c
+++ b/src/libui_sdl/libui/unix/draw.c
@@ -163,7 +163,7 @@ uiDrawBitmap* uiDrawNewBitmap(uiDrawContext* c, int width, int height)
 
 void uiDrawBitmapUpdate(uiDrawBitmap* bmp, const void* data)
 {
-    unsigned char* src = data;
+    const unsigned char* src = data;
     unsigned char* dst = cairo_image_surface_get_data(bmp->bmp);
     
     if (bmp->Stride == bmp->Width*4)
diff --git a/src/libui_sdl/libui/unix/stddialogs.c b/src/libui_sdl/libui/unix/stddialogs.c
index d2b89b97..3daeffac 100644
--- a/src/libui_sdl/libui/unix/stddialogs.c
+++ b/src/libui_sdl/libui/unix/stddialogs.c
@@ -6,7 +6,7 @@
 
 #define windowWindow(w) ((w)?(GTK_WINDOW(uiControlHandle(uiControl(w)))):NULL)
 
-static char *filedialog(GtkWindow *parent, GtkFileChooserAction mode, const gchar *confirm, char* filter, char* initpath)
+static char *filedialog(GtkWindow *parent, GtkFileChooserAction mode, const gchar *confirm, const char* filter, const char* initpath)
 {
 	GtkWidget *fcd;
 	GtkFileChooser *fc;
@@ -83,12 +83,12 @@ static char *filedialog(GtkWindow *parent, GtkFileChooserAction mode, const gcha
 	return filename;
 }
 
-char *uiOpenFile(uiWindow *parent, char* filter, char* initpath)
+char *uiOpenFile(uiWindow *parent, const char* filter, const char* initpath)
 {
 	return filedialog(windowWindow(parent), GTK_FILE_CHOOSER_ACTION_OPEN, "_Open", filter, initpath);
 }
 
-char *uiSaveFile(uiWindow *parent, char* filter, char* initpath)
+char *uiSaveFile(uiWindow *parent, const char* filter, const char* initpath)
 {
 	return filedialog(windowWindow(parent), GTK_FILE_CHOOSER_ACTION_SAVE, "_Save", filter, initpath);
 }
diff --git a/src/libui_sdl/libui/windows/stddialogs.cpp b/src/libui_sdl/libui/windows/stddialogs.cpp
index eb535cbe..d0fd506a 100644
--- a/src/libui_sdl/libui/windows/stddialogs.cpp
+++ b/src/libui_sdl/libui/windows/stddialogs.cpp
@@ -16,7 +16,7 @@
 
 #define windowHWND(w) (w ? (HWND) uiControlHandle(uiControl(w)) : NULL)
 
-char *commonItemDialog(HWND parent, REFCLSID clsid, REFIID iid, char* filter, char* initpath, FILEOPENDIALOGOPTIONS optsadd)
+char *commonItemDialog(HWND parent, REFCLSID clsid, REFIID iid, const char* filter, const char* initpath, FILEOPENDIALOGOPTIONS optsadd)
 {
 	IFileDialog *d = NULL;
 	FILEOPENDIALOGOPTIONS opts;
@@ -108,7 +108,7 @@ out:
 	return name;
 }
 
-char *uiOpenFile(uiWindow *parent, char* filter, char* initpath)
+char *uiOpenFile(uiWindow *parent, const char* filter, const char* initpath)
 {
 	char *res;
 
@@ -121,7 +121,7 @@ char *uiOpenFile(uiWindow *parent, char* filter, char* initpath)
 	return res;
 }
 
-char *uiSaveFile(uiWindow *parent, char* filter, char* initpath)
+char *uiSaveFile(uiWindow *parent, const char* filter, const char* initpath)
 {
 	char *res;