What cause iPhone 7/7 Plus reports iTunes error 4013?

We can always hear that iPhone reports iTunes error 4013. This issue is common to the iPhone 6S to iPhone 7 Plus. Today we are going to talk about the iPhone 7/7P stuck on white Apple and then restart; when we use iTunes to flash it, it reports unknow error 4013. What cause this porblem? Vip Pro Shop Team analysis is as follows

Flash iPhone with iTunes and then it reports unknown error 4013 common fault is usually caused by iPhone baseband CPU and 19.2 crystal oscillator.

To find out if the baseband caused the problem, you can replace the new iPhone baseband CPU, and the brush it again, see if iTunes will reports unknown error -1. If it does report an unknown error -1, this indicates that the original baseband damage caused that problem.

To determine whether it is a 19.2M problem, you can directly replace the new 19.2 crystal oscillator, and then use iTunes to brush it again.

Also, if the baseband power supply was damaged, the iPhone will show same issue. 

How to fix iPhone 7 WIFI cannot be turn on?

We got an iPhone 7 to repair from customer, the fault is that the iPhone has been dropped, the Bluetooth can be turned on, but the WIFI icon is gray and cannot be opened. When we got the iPhone, we press the iPhone power button, and test the other functions first, all is fine, and the only problem is WIFI cannot be turn on.

After we enter the IOS system, we still cannot see the MAC address of WIFI, as shown in picture 9-5-1.

Not even Wi-Fi addresses like this are basically caused by the iPhone CPU does not recognize the iPhone Wi-Fi chip, the customer said the iPhone has been dropped, we suspect that the chip was damaged or empty solder. Test the Wi-Fi working conditions before removing the chip.

Use multimeter to measure the diode data, no problem found, is it really the Wi-Fi chip that's broken? Now we only can remove it and replace the new one. To replace the iPhone 7 Wi-Fi chip, you need to remove iPhone NAND flash and unlock. Now, we remove the Wi-Fi chip, and then we found that the solder pad of Wi-Fi chip dropped four points, the position of circuit diagram as follows

These pins are on the PCIE bus, and it passes through coupling capacitor to the CPU. Ready to replace the chip, but replacing the chip requires removing the NAND flash, so we’re trying to make up the pins on the chip. Scrape out solder joints, weld the jump wire, and paint the green UV oil, and then plant Tin, welding it with rework station. Well-welded chip as shown in the picture 9-5-3.

                                        

The small pins on the edge of the chip can be used to test whether it is properly welded. After welding, measure the diode data with multimeter, it is normal. Boot it and test it, the failure has been repaired.

Finally, we can see the WIFI address on the phone, which shows the A10 CPU has already identified the chip. The WIFI can be turn on now, as shown in the picture 9-5-7. Test it for a period of time, all is fine, send the iPhone 7 back to the customer.