diff --git a/doc/buildAndProgram.md b/doc/buildAndProgram.md
index cf349094..afd526e0 100644
--- a/doc/buildAndProgram.md
+++ b/doc/buildAndProgram.md
@@ -3,6 +3,7 @@
 To build this project, you'll need:
  - A cross-compiler : [ARM-GCC (9-2020-q2-update)](https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm/downloads/9-2020-q2-update)
  - The NRF52 SDK 15.3.0 : [nRF-SDK v15.3.0](https://developer.nordicsemi.com/nRF5_SDK/nRF5_SDK_v15.x.x/nRF5_SDK_15.3.0_59ac345.zip)
+ - The `cbor` and `intelhex` modules for Python 3
  - A reasonably recent version of CMake (I use 3.16.5)
 
 ## Build steps 
diff --git a/src/displayapp/screens/StopWatch.cpp b/src/displayapp/screens/StopWatch.cpp
index e06981af..d7cd20c3 100644
--- a/src/displayapp/screens/StopWatch.cpp
+++ b/src/displayapp/screens/StopWatch.cpp
@@ -115,8 +115,9 @@ bool StopWatch::Refresh() {
     // Init state when an user first opens the app
     // and when a stop/reset button is pressed
     case States::Init: {
-      if (btnStopLap) {
+      if (btnStopLap != nullptr) {
         lv_obj_del(btnStopLap);
+        btnStopLap = nullptr;
       }
       // The initial default value
       lv_label_set_text(time, "00:00");
diff --git a/src/displayapp/screens/SystemInfo.cpp b/src/displayapp/screens/SystemInfo.cpp
index f6e8d61a..ab349d7b 100644
--- a/src/displayapp/screens/SystemInfo.cpp
+++ b/src/displayapp/screens/SystemInfo.cpp
@@ -70,8 +70,8 @@ std::unique_ptr<Screen> SystemInfo::CreateScreen1() {
                         "#FFFF00 InfiniTime#\n\n"
                         "#444444 Version# %ld.%ld.%ld\n\n"
                         "#444444 Build date#\n"
-                        "\t%s\n"
-                        "\t%s\n",
+                        "%s\n"
+                        "%s\n",
                         Version::Major(),
                         Version::Minor(),
                         Version::Patch(),
@@ -242,4 +242,4 @@ std::unique_ptr<Screen> SystemInfo::CreateScreen5() {
   lv_label_set_align(label, LV_LABEL_ALIGN_CENTER);
   lv_obj_align(label, lv_scr_act(), LV_ALIGN_CENTER, 0, 0);
   return std::unique_ptr<Screen>(new Screens::Label(4, 5, app, label));
-}
\ No newline at end of file
+}