diff --git a/grid_common/grid_lua.c b/grid_common/grid_lua.c
index 211991d55..5e412a126 100644
--- a/grid_common/grid_lua.c
+++ b/grid_common/grid_lua.c
@@ -90,7 +90,7 @@ void grid_lua_clear_stdo(struct grid_lua_model* lua) { memset(lua->stdo, 0, lua-
 
 void grid_lua_clear_stde(struct grid_lua_model* lua) { memset(lua->stde, 0, lua->stde_len); }
 
-int grid_lua_append_stdo(struct grid_lua_model* lua, char* str) {
+int grid_lua_append_stdo(struct grid_lua_model* lua, const char* str) {
 
   int curr = strnlen(lua->stdo, lua->stdo_len);
 
@@ -107,7 +107,7 @@ int grid_lua_append_stdo(struct grid_lua_model* lua, char* str) {
   return 0;
 }
 
-int grid_lua_append_stde(struct grid_lua_model* lua, char* str) {
+int grid_lua_append_stde(struct grid_lua_model* lua, const char* str) {
 
   int curr = strnlen(lua->stde, lua->stde_len);
 
diff --git a/grid_common/grid_lua.h b/grid_common/grid_lua.h
index 34dded7e4..e57e907f5 100644
--- a/grid_common/grid_lua.h
+++ b/grid_common/grid_lua.h
@@ -62,8 +62,8 @@ void grid_lua_clear_stdi(struct grid_lua_model* lua);
 void grid_lua_clear_stdo(struct grid_lua_model* lua);
 void grid_lua_clear_stde(struct grid_lua_model* lua);
 
-int grid_lua_append_stdo(struct grid_lua_model* lua, char* str);
-int grid_lua_append_stde(struct grid_lua_model* lua, char* str);
+int grid_lua_append_stdo(struct grid_lua_model* lua, const char* str);
+int grid_lua_append_stde(struct grid_lua_model* lua, const char* str);
 
 char* grid_lua_get_output_string(struct grid_lua_model* lua);
 char* grid_lua_get_error_string(struct grid_lua_model* lua);
diff --git a/grid_common/grid_lua_api.c b/grid_common/grid_lua_api.c
index 394aaeaa6..b4065b015 100644
--- a/grid_common/grid_lua_api.c
+++ b/grid_common/grid_lua_api.c
@@ -2196,7 +2196,12 @@ int l_grid_cat(lua_State* L) {
       return 0;
     }
 
-    int32_t min = lua_tointeger(L, -1);
+    int32_t min = 0;
+
+    if (ele->type == GRID_PARAMETER_ELEMENT_BUTTON) {
+      min = lua_tointeger(L, -1);
+    }
+
     lua_pop(L, 1);
 
     grid_cal_but_min_set(cal_but, i, min);
@@ -2209,7 +2214,12 @@ int l_grid_cat(lua_State* L) {
       return 0;
     }
 
-    int32_t max = lua_tointeger(L, -1);
+    int32_t max = 0;
+
+    if (ele->type == GRID_PARAMETER_ELEMENT_BUTTON) {
+      max = lua_tointeger(L, -1);
+    }
+
     lua_pop(L, 1);
 
     grid_cal_but_max_set(cal_but, i, max);
diff --git a/grid_common/grid_msg.c b/grid_common/grid_msg.c
index 9b2ac55e3..43ed41b09 100644
--- a/grid_common/grid_msg.c
+++ b/grid_common/grid_msg.c
@@ -531,7 +531,7 @@ int grid_str_verify_frame(char* message, uint16_t length) {
   return 0;
 }
 
-uint32_t grid_str_set_segment_char(char* dest, uint8_t head_hexes, uint32_t size, char* buffer) {
+uint32_t grid_str_set_segment_char(char* dest, uint8_t head_hexes, uint32_t size, const char* buffer) {
 
   switch (head_hexes) {
   case 2:
diff --git a/grid_common/grid_msg.h b/grid_common/grid_msg.h
index 8e5bc860c..de688570e 100644
--- a/grid_common/grid_msg.h
+++ b/grid_common/grid_msg.h
@@ -131,7 +131,7 @@ void grid_str_write_hex_string_value(char* start_location, uint8_t size, uint32_
 
 int grid_str_verify_frame(char* message, uint16_t length);
 
-uint32_t grid_str_set_segment_char(char* dest, uint8_t head_bytes, uint32_t size, char* buffer);
+uint32_t grid_str_set_segment_char(char* dest, uint8_t head_bytes, uint32_t size, const char* buffer);
 uint32_t grid_str_get_segment_char(char* src, uint8_t head_hexes, uint32_t max_size, char* buffer);
 
 #endif /* GRID_MSG_H */
diff --git a/grid_esp/components/grid_esp32_module_tek1/grid_esp32_module_tek1.c b/grid_esp/components/grid_esp32_module_tek1/grid_esp32_module_tek1.c
index b76896ee3..dcc6cecc8 100644
--- a/grid_esp/components/grid_esp32_module_tek1/grid_esp32_module_tek1.c
+++ b/grid_esp/components/grid_esp32_module_tek1/grid_esp32_module_tek1.c
@@ -228,11 +228,9 @@ void grid_esp32_module_tek1_init(struct grid_sys_model* sys, struct grid_ui_mode
                                  struct grid_esp32_lcd_model* lcds) {
 
   // Allocate transfer buffer
-  uint32_t width = LCD_HRES;
   uint32_t height = LCD_VRES;
   uint32_t lcd_tx_lines = 16;
   uint32_t lcd_tx_bytes = height * lcd_tx_lines * COLMOD_RGB888_BYTES;
-  // uint8_t* xferbuf = malloc(lcd_tx_bytes);
 
   // Initialize LCD
   grid_esp32_lcd_spi_bus_init(lcd_tx_bytes);
diff --git a/grid_esp/components/grid_esp32_usb/grid_esp32_usb.c b/grid_esp/components/grid_esp32_usb/grid_esp32_usb.c
index 0fd6a87f7..99599922b 100644
--- a/grid_esp/components/grid_esp32_usb/grid_esp32_usb.c
+++ b/grid_esp/components/grid_esp32_usb/grid_esp32_usb.c
@@ -41,7 +41,6 @@ void tud_midi_rx_cb(uint8_t itf) {
   // regardless of these being used or not. Therefore incoming traffic should be
   // read (possibly just discarded) to avoid the sender blocking in IO
   uint8_t packet[4];
-  bool read = false;
 
   while (tud_midi_available()) {