iPhone 6S cannot turn on caused by damaged baseband CPU

This iPhone 6S was dropped into the ground, and then it cannot turn on. Why is that? Let's take a look at the faulty details.

The iphone 6s sometimes it can be online, but sometimes cannot. Online state is not normal, drive also displays incorrectly, this phenomenon is usually caused by virtual soler on CPU.

After soldering CPU with soldering station, the iPhone 6s can be normal online, but it displays error 4013 when flashing system.

For iPhone 6S device, if this phenomenon happens, which are generally baseband problems, so we remove the baseband, indeed some tin points come off. We can see it clearly under the microscope. As shown in picture 1.

Make jumper on the disconnected but useful pin, install chip on it, but it still shows error 4013 when flashing, seems there is still a problem exist. Rooting the device repeatedly, we find when white apple appears, baseband S3, S4, S5 voltage can be instantly measured with power supply besides S2, but we still can measure the ground value on S2, is it the baseband power failure? Remove the baseband power supply chip, by the way of measuring its pin, it is found that the 91 and 97 pin of the baseband power supply chip are blocked. so we can see the problem has been found here, as shown in picture 2. Remove the inductance, its pin has been damagd. The front is good while the reverse falls a pin. As shown in picture 3.

So we replace the damaged parts and install original fingerprint, the progress bar is normal when flashing now, as shown in picture 4.