diff --git a/minui/graphics.cpp b/minui/graphics.cpp
index 3b38601..c1aab41 100644
--- a/minui/graphics.cpp
+++ b/minui/graphics.cpp
@@ -356,6 +356,10 @@
 
   gr_flip();
   gr_flip();
+  if (!gr_draw) {
+    printf("gr_init: gr_draw becomes nullptr after gr_flip\n");
+    return -1;
+  }
 
   gr_rotate(DEFAULT_ROTATION);
 
diff --git a/minui/graphics_drm.cpp b/minui/graphics_drm.cpp
index e7d4b38..4c98507 100644
--- a/minui/graphics_drm.cpp
+++ b/minui/graphics_drm.cpp
@@ -45,15 +45,17 @@
   }
 }
 
-void MinuiBackendDrm::DrmEnableCrtc(int drm_fd, drmModeCrtc* crtc, GRSurfaceDrm* surface) {
-  int32_t ret = drmModeSetCrtc(drm_fd, crtc->crtc_id, surface->fb_id, 0, 0,  // x,y
-                               &main_monitor_connector->connector_id,
-                               1,  // connector_count
-                               &main_monitor_crtc->mode);
+int MinuiBackendDrm::DrmEnableCrtc(int drm_fd, drmModeCrtc* crtc, GRSurfaceDrm* surface) {
+  int ret = drmModeSetCrtc(drm_fd, crtc->crtc_id, surface->fb_id, 0, 0,  // x,y
+                           &main_monitor_connector->connector_id,
+                           1,  // connector_count
+                           &main_monitor_crtc->mode);
 
   if (ret) {
     printf("drmModeSetCrtc failed ret=%d\n", ret);
   }
+
+  return ret;
 }
 
 void MinuiBackendDrm::Blank(bool blank) {
@@ -368,7 +370,10 @@
 
   current_buffer = 0;
 
-  DrmEnableCrtc(drm_fd, main_monitor_crtc, GRSurfaceDrms[1]);
+  // We will likely encounter errors in the backend functions (i.e. Flip) if EnableCrtc fails.
+  if (DrmEnableCrtc(drm_fd, main_monitor_crtc, GRSurfaceDrms[1]) != 0) {
+    return nullptr;
+  }
 
   return GRSurfaceDrms[0];
 }
diff --git a/minui/graphics_drm.h b/minui/graphics_drm.h
index de96212..756625b 100644
--- a/minui/graphics_drm.h
+++ b/minui/graphics_drm.h
@@ -42,7 +42,7 @@
 
  private:
   void DrmDisableCrtc(int drm_fd, drmModeCrtc* crtc);
-  void DrmEnableCrtc(int drm_fd, drmModeCrtc* crtc, GRSurfaceDrm* surface);
+  int DrmEnableCrtc(int drm_fd, drmModeCrtc* crtc, GRSurfaceDrm* surface);
   GRSurfaceDrm* DrmCreateSurface(int width, int height);
   void DrmDestroySurface(GRSurfaceDrm* surface);
   void DisableNonMainCrtcs(int fd, drmModeRes* resources, drmModeCrtc* main_crtc);
diff --git a/screen_ui.cpp b/screen_ui.cpp
index b9aba80..b4ef054 100644
--- a/screen_ui.cpp
+++ b/screen_ui.cpp
@@ -173,7 +173,9 @@
 
 ScreenRecoveryUI::~ScreenRecoveryUI() {
   progress_thread_stopped_ = true;
-  progress_thread_.join();
+  if (progress_thread_.joinable()) {
+    progress_thread_.join();
+  }
 }
 
 GRSurface* ScreenRecoveryUI::GetCurrentFrame() const {
diff --git a/tests/unit/rangeset_test.cpp b/tests/unit/rangeset_test.cpp
index 7ae193e..fc72f2f 100644
--- a/tests/unit/rangeset_test.cpp
+++ b/tests/unit/rangeset_test.cpp
@@ -209,6 +209,7 @@
   ASSERT_EQ(static_cast<size_t>(6), rs.GetBlockNumber(5));
   ASSERT_EQ(static_cast<size_t>(9), rs.GetBlockNumber(8));
 
+  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
   // Out of bound.
   ASSERT_EXIT(rs.GetBlockNumber(9), ::testing::KilledBySignal(SIGABRT), "");
 }
@@ -284,6 +285,8 @@
 
   ASSERT_EQ(static_cast<size_t>(10), rs.GetOffsetInRangeSet(4106));
   ASSERT_EQ(static_cast<size_t>(40970), rs.GetOffsetInRangeSet(4096 * 16 + 10));
+
+  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
   // block#10 not in range.
   ASSERT_EXIT(rs.GetOffsetInRangeSet(40970), ::testing::KilledBySignal(SIGABRT), "");
 }
diff --git a/tests/unit/screen_ui_test.cpp b/tests/unit/screen_ui_test.cpp
index 2562307..a3dd2ad 100644
--- a/tests/unit/screen_ui_test.cpp
+++ b/tests/unit/screen_ui_test.cpp
@@ -293,6 +293,11 @@
   ASSERT_FALSE(ui_->WasTextEverVisible());
 }
 
+TEST_F(ScreenRecoveryUITest, dtor_NotCallingInit) {
+  ui_.reset();
+  ASSERT_FALSE(ui_);
+}
+
 TEST_F(ScreenRecoveryUITest, ShowText) {
   ASSERT_TRUE(ui_->Init(kTestLocale));
   ASSERT_FALSE(ui_->IsTextVisible());
@@ -408,5 +413,7 @@
   ASSERT_TRUE(ui_->Init(kTestLocale));
   TemporaryDir resource_dir;
   Paths::Get().set_resource_dir(resource_dir.path);
+
+  ::testing::FLAGS_gtest_death_test_style = "threadsafe";
   ASSERT_EXIT(ui_->RunLoadAnimation(), ::testing::KilledBySignal(SIGABRT), "");
 }
diff --git a/ui.cpp b/ui.cpp
index 51d7f12..6c91d01 100644
--- a/ui.cpp
+++ b/ui.cpp
@@ -78,7 +78,9 @@
 RecoveryUI::~RecoveryUI() {
   ev_exit();
   input_thread_stopped_ = true;
-  input_thread_.join();
+  if (input_thread_.joinable()) {
+    input_thread_.join();
+  }
 }
 
 void RecoveryUI::OnKeyDetected(int key_code) {