I have to provide an update mechanism to a product. Currently, I implemented a bluetooth upgrade mechanism, updated pushed via Bluetooth. In case something goes very wrong, marketing asking for a recovery method, which is reasonable.
The uP I use has an embedded bootloader (ROM). I can use this as the bullet proof method. This one requires some pin to be pulled high, original design we didn't expose this, it was a pad on the board. Now, I need some way to expose and give user a way to make this work. The thinking is to use a special power on/off button. Currently, we use a mechanical button, when off, no power to system including CPU. The idea is to find a button, if you keep pressed at the bottom, this pin is pulled high and if you have the right software on PC, things will start to move.
What do you think about this approach? (I am worried about hackers) and where can I find such a switch?