So, how does the transistor T3 (inside the red box) turn on?
I guess T3 base is not connected to ground because T1 (inside the blue box) isn't active, or is it?
In order for to T1 activate, the MCU needs to pull up T1 base via R8 but it needs power to do so and power is only delivered to the MCU via T3.
I know there's something wrong with my beginner's analysis. Could some pro show me the way?
By the way, the full schematic can be found here (page 10).