Fix DANGEROUS comments.

Hardware-Preparation.md

@@ -8,11 +8,16 @@ Be careful - some so called 3V3 FTDI cables actually supply 5v on the VCC line.
 
 ### Attention ⚠️️⚠️️⚠️️
 
-**Be extremely careful if connecting to AC while the cover is open and circuit board is exposed**
+**DO NOT CONNECT TO MAINS AC WHILE THE COVER IS OPEN AND CIRCUIT BOARD IS EXPOSED** 
 
-Shorting your serial interface with AC will fry your module or programmer and may also harm or destroy your PC. If you are not careful, your own health might be in danger. It is preferable to always have all high power cables disconnected from the Sonoff module while being connected via serial/USB or even while the case of the module is opened.
+**NEVER TRY TO FLASH A SONOFF WHILE IT IS CONNECTED TO MAINS AC** 
 
-Note that contrary to alarmist reports circulating on the internet, the DC power supply is fully isolated from the AC supply. It is perfectly safe to interface with the DC circuit while the unit is connected to AC supply, as long as the GND is tied in common. It is also preferable to keep the +3.3V line disconnected while interfacing with the sonoff self powered. If the sonoff is self-powered (connected to AC), connect only GND, TX, RX.
+**A SONOFF IS NOT A TOY. YOU CAN BE ELECTROCUTED IF YOU DON'T KNOW WHAT YOU ARE DOING**
+
+If you are not careful, your own health will be in danger.	
+
+Also, shorting your serial interface with AC will fry your module or programmer and will also harm or destroy your PC.	
+It is a must to always have all high power cables disconnected from the Sonoff module while being connected via serial/USB or even while the case of the module is opened.
 
 ## Serial Connection