Added removal of ToF cover and knowledge graph to MC flash

book/opmanual_duckiebot/atoms_17_operation_manual_duckiebot/1_5_hw_assembly_db21m.md

@@ -60,7 +60,7 @@ Note: "The Duckiebox hides but does not steal". Your Duckiebot chassis is under
 
 Although not necessary, a small (M2.5) wrench might ease some of the next passages.
 
-Note: we currently support the NVIDIA Jetson Nano 2GB developer kit, not 4GB. 
+Note: we currently support the NVIDIA Jetson Nano 2GB developer kit, not 4GB.
 
 ### Plastic cover
 
@@ -552,12 +552,18 @@ Note: The orientation of the cable should be such that the blue part of the cabl
 </div>
 
 ### Step 55
-Attach the small blue distance sensor to the stand-off on the front bumper and tighten it with a nylon M3 nut (`N4`). Make sure to take off the small transparent cover from the sensor.
+Attach the small blue distance sensor to the stand-off on the front bumper and tighten it with a nylon M3 nut (`N4`).
 
 <div figure-id="fig:db21m-step_55">
      <img src="db21-step_55.png" style='width: 40em' />
 </div>
 
+Make sure to take off the small transparent cover from the sensor.
+
+<div figure-id="fig:db21m-step_55A">
+     <img src="db21-step_55A.png" style='width: 15em' />
+</div>
+
 ### Step 56
 Take the shortest 4-pin cable and connect the bottom of the time of flight sensor to the front bumper, as shown below.
 

book/opmanual_duckiebot/atoms_17_operation_manual_duckiebot/4_4_debug_reflash_mc.md

@@ -1,5 +1,17 @@
 # Debug - Reflash Microcontroller {#reflash-microcontroller status=ready}
 
+This page is only for the DB18 and DB19 configuration (not the DB21M).
+
+<div class='requirements' markdown="1">
+
+Requires: A Duckiebot DB18 or DB19.
+
+Requires: A stable network connection to your Duckiebot.
+
+Result: A flashed microcontroller (not SD card) on the HUT board with the latest code.
+
+</div>
+
 Warning: You do not need to perform the following procedure unless you are specifically told to do in the book.
 
 The LEDs of the Duckiebot should light up in white as soon as you power the Duckiebot. If the LEDs turn on and shine in any different color than white, probably the code on the microcontroller is corrupted. You can reflash it using the following procedure: