Docs: Clarify Musca flashing process

Expands the Musca board flashing instructions to clarify the steps that
need to be followed to successfully flash the board.

Change-Id: I90ec9e6584b2ff52e06e235f872eea16ea261088
Signed-off-by: Jamie Fox <jamie.fox@arm.com>
diff --git a/docs/user_guides/tfm_user_guide.rst b/docs/user_guides/tfm_user_guide.rst
index ec2bf9e..754a99f 100644
--- a/docs/user_guides/tfm_user_guide.rst
+++ b/docs/user_guides/tfm_user_guide.rst
@@ -220,35 +220,38 @@
 Example application with BL2 bootloader
 =======================================
 
-#. Create a unified hex file comprising of both mcuboot and tfm_sign
-   binary
+#. Create a unified hex file comprising of both ``mcuboot.bin`` and
+   ``tfm_sign.bin``.
 
--  For Musca-A
+    - For Musca-A
 
-   - Windows::
+        - Windows::
 
-      srec_cat.exe bl2\ext\mcuboot\mcuboot.bin -Binary -offset 0x200000 tfm_sign.bin -Binary -offset 0x220000 -o tfm.hex -Intel
+            srec_cat.exe bl2\ext\mcuboot\mcuboot.bin -Binary -offset 0x200000 tfm_sign.bin -Binary -offset 0x220000 -o tfm.hex -Intel
 
-   - Linux::
+        - Linux::
 
-      srec_cat bl2/ext/mcuboot/mcuboot.bin -Binary -offset 0x200000 tfm_sign.bin -Binary -offset 0x220000 -o tfm.hex -Intel
+            srec_cat bl2/ext/mcuboot/mcuboot.bin -Binary -offset 0x200000 tfm_sign.bin -Binary -offset 0x220000 -o tfm.hex -Intel
 
--  For Musca-B1
+    - For Musca-B1
 
-   - Windows::
+        - Windows::
 
-      srec_cat.exe bl2\ext\mcuboot\mcuboot.bin -Binary -offset 0xA000000 tfm_sign.bin -Binary -offset 0xA020000 -o tfm.hex -Intel
+            srec_cat.exe bl2\ext\mcuboot\mcuboot.bin -Binary -offset 0xA000000 tfm_sign.bin -Binary -offset 0xA020000 -o tfm.hex -Intel
 
-   - Linux::
+        - Linux::
 
-      srec_cat bl2/ext/mcuboot/mcuboot.bin -Binary -offset 0xA000000 tfm_sign.bin -Binary -offset 0xA020000 -o tfm.hex -Intel
+            srec_cat bl2/ext/mcuboot/mcuboot.bin -Binary -offset 0xA000000 tfm_sign.bin -Binary -offset 0xA020000 -o tfm.hex -Intel
 
-#. Plug the Musca board into your computer. The board should appear as a USB
-   drive
-#. Copy ``tfm.hex`` to the USB drive
-#. Reset the board to execute the TF-M example application
-#. After completing the procedure you should be able to see on the UART0
-   (baud 115200 8n1) the following messages::
+#. Power up the Musca board by connecting it to a computer with a USB lead.
+   Press the ``PBON`` button if the green ``ON`` LED does not immediately turn
+   on. The board should appear as a USB drive.
+#. Copy ``tfm.hex`` to the USB drive. The orange ``PWR`` LED should start
+   blinking.
+#. Once the ``PWR`` LED stops blinking, power cycle or reset the board to boot
+   from the new image.
+#. After completing the procedure you should see the following messages on the
+   DAPLink UART (baud 115200 8n1)::
 
     [INF] Starting bootloader
     [INF] Image 0: magic=good, copy_done=0xff, image_ok=0xff
@@ -262,7 +265,7 @@
 Regression tests with BL2 bootloader
 ====================================
 After completing the procedure you should see the following messages on the
-UART0 (baud 115200 8n1)::
+DAPLink UART (baud 115200 8n1)::
 
     [INF] Starting bootloader
     [INF] Image 0: magic=good, copy_done=0xff, image_ok=0xff