feat(core/bootloader): tweak initial screens

* do not wait for user touch when we know we are going to the welcome
  screen
* do not fade before the Trezor Model T screen

core/embed/bootloader/main.c

@@ -351,7 +351,7 @@ int bootloader_main(void) {
   // anyway
   uint32_t touched = 0;
 #ifdef USE_TOUCH
-  if (stay_in_bootloader != sectrue) {
+  if (firmware_present == sectrue && stay_in_bootloader != sectrue) {
     for (int i = 0; i < 100; i++) {
       touched = touch_is_detected() | touch_read();
       if (touched) {
@@ -373,6 +373,11 @@ int bootloader_main(void) {
 
   // start the bootloader if no or broken firmware found ...
   if (firmware_present != sectrue) {
+#ifdef TREZOR_EMULATOR
+    // wait a bit so that the empty lock icon is visible
+    // (on a real device, we are waiting for touch init which takes longer)
+    hal_delay(400);
+#endif
     // ignore stay in bootloader
     stay_in_bootloader = secfalse;
     touched = false;

core/embed/rust/src/ui/model_tt/bootloader/mod.rs

@@ -113,6 +113,7 @@ where
     };
     display::sync();
     frame.paint();
+    display::refresh();
     if fading {
         fadein()
     };
@@ -430,7 +431,7 @@ extern "C" fn screen_install_success(
 #[no_mangle]
 extern "C" fn screen_welcome_model() {
     let mut frame = WelcomeScreen::new();
-    show(&mut frame, true);
+    show(&mut frame, false);
 }
 
 #[no_mangle]