diff --git a/midi2cv/makefile b/midi2cv/makefile
index 1a63bf6..001d276 100644
--- a/midi2cv/makefile
+++ b/midi2cv/makefile
@@ -24,14 +24,14 @@
 # See http://creativecommons.org/licenses/MIT/ for more information.
 
 # System specifications
-F_CRYSTAL      = 8000000L
-F_CPU          = 72000000L
-SYSCLOCK       = SYSCLK_FREQ_72MHz
-FAMILY         = f37x
-# USB            = enabled
-U8G2           = enabled
+F_CRYSTAL         = 8000000L
+F_CPU             = 72000000L
+SYSCLOCK          = SYSCLK_FREQ_72MHz
+FAMILY            = f37x
+# USB             = enabled
+U8G2              = enabled
 APPLICATION_LARGE = TRUE
-BOOTLOADER     = midi2cv_bootloader
+BOOTLOADER        = midi2cv_bootloader
 
 # Preferred upload command
 UPLOAD_COMMAND  = upload_combo_jtag
@@ -46,7 +46,5 @@ PACKAGES       = midi2cv \
                  stmlib/system
 RESOURCES      = midi2cv/resources
 
-TOOLCHAIN_PATH ?= /usr/local/arm-4.8.3/
-
 include stmlib/makefile.inc
 
diff --git a/midi2cv/ui.cc b/midi2cv/ui.cc
index a131d44..afc3c32 100644
--- a/midi2cv/ui.cc
+++ b/midi2cv/ui.cc
@@ -61,7 +61,7 @@ void UI::Flush()
   display.Flush();
 }
 
-bool UI::DoEvents()
+void UI::DoEvents()
 {
   bool refresh_display = false;
   while (input_queue.available()) {
@@ -84,8 +84,6 @@ bool UI::DoEvents()
     input_queue.Touch();
     Draw();
   }
-
-  return refresh_display;
 }
 
 void UI::OnClick()
diff --git a/midi2cv/ui.h b/midi2cv/ui.h
index 1b30a11..fdafffd 100644
--- a/midi2cv/ui.h
+++ b/midi2cv/ui.h
@@ -20,7 +20,7 @@ class UI {
   void Init();
   void Poll();
   void Flush();
-  bool DoEvents();
+  void DoEvents();
 
   private:
   Menu_t current_menu;
diff --git a/stmlib b/stmlib
index e14f6eb..0f1dc19 160000
--- a/stmlib
+++ b/stmlib
@@ -1 +1 @@
-Subproject commit e14f6eb13096d6ed648d140e730c541ba4fd702d
+Subproject commit 0f1dc19f23d34b6f282558794bc089a147015d4f