-
• #1
-
• #2
It's so you can update the firmware via DFU on BLE. If you don't want to do that then you can leave it out
-
• #3
does it support update firmware by serial port ( RX:29, TX:28) ? can it flash arduino sketch by by serial port ( RX:29, TX:28) ?
-
• #4
No to both I'm afraid. You could make your own bootloader that did that if you needed.