Address reviews

examples/boot-usb-dfu/.cargo/config.toml

@@ -1,9 +0,0 @@
-[unstable]
-build-std = ["core"]
-build-std-features = ["panic_immediate_abort"]
-
-[build]
-target = "thumbv7em-none-eabi"
-
-[env]
-DEFMT_LOG = "trace"

examples/boot/application/stm32wb-dfu/Cargo.toml

@@ -25,6 +25,7 @@ cortex-m-rt = "0.7.0"
 [features]
 defmt = [
       "dep:defmt",
+      "dep:defmt-rtt",
       "embassy-stm32/defmt",
       "embassy-boot-stm32/defmt",
       "embassy-sync/defmt",

examples/boot/bootloader/stm32wb-dfu/src/main.rs

@@ -26,13 +26,12 @@ fn main() -> ! {
     config.rcc = WPAN_DEFAULT;
     let p = embassy_stm32::init(config);
 
-    // Uncomment this if you are debugging the bootloader with debugger/RTT attached,
-    // as it prevents a hard fault when accessing flash 'too early' after boot.
-    /*
-        for i in 0..10000000 {
-            cortex_m::asm::nop();
-        }
-    */
+    // Prevent a hard fault when accessing flash 'too early' after boot.
+    #[cfg(feature = "defmt")]
+    for _ in 0..10000000 {
+        cortex_m::asm::nop();
+    }
+    
 
     let layout = Flash::new_blocking(p.FLASH).into_blocking_regions();
     let flash = Mutex::new(RefCell::new(layout.bank1_region));