The mobile phones as a daily necessity, it plays an important role in our life. Many people think it can't leave it. when phone was broken, you may fix quickly. Vipprog engineer recommend you the fix method of iPhone 6S Plus displays white Apple logo and then reboots.

Issue:

The dropped iPhone displays white Apple logo after power on. It has been repaired once but did not fix well.

Fix process:

1. First root and check the error code. iTunes’ error code is 4013. It will display UDID information when using ihelp software to root. The showing of white Apple logo and reboot and reporting error code 4013 is because of the damage of NAND Flash IC. But this iPhone can show UDID information, so NAND FLASH IC is not likely to be damaged.

2. After teardown, we find the motherboard has been fixed many times. CPU, EEPROM and USB chip are all rewelded. First clean the remaining soldering paste and observe whether these welded places has any component dropping off under microscope. After making sure no component dropping off, replace the NAND Flash and root. But iPhone still reports error code 4013. The problem in CPU is less likely happen.

3. After checking my repairing notes, there is a same problem happens because of the short circuit of iPhone 6S power IC. Remove the baseband chip and iPhone displays white Apple logo and reboot later. Replace a new baseband power chip and everything becomes normal. After researching the iPhone working principles, we find iPhone 6S baseband chip communicate with CPU by PCIE bus. During the power on process, the PCIE bus will be initialized. Therefore, the improper work of baseband will lead to white Apple loge showing when power on.

4. Find a normal iPhone 6S and reboot it. Measure the baseband power supply when it shows white Apple logo. The power supply exists already and the working condition for baseband has been satisfied. The baseband supply’s bitmap is shown in below picture.

5. Root the faulty motherboard and measure the baseband power supply when the white Apple logo is showing. We find that PP_0V9_SMPS1 and PP_1V0_SMPS3’s power supply has been produced, while PP_1V225_SMPS2 and PP_1V85_SMPS4 has not.

6. That suggests there is nothing wrong with baseband power. It is very likely that the baseband chip is empty soldered or damaged. The circuit diagram of baseband power supply is shown in below picture.

7. Remove the baseband and measure the diode data of the circuit towards chip and CPU. The data is normal. Tin the baseband chip and weld it on motherboard. Root it and everything becomes normal.

Trouble is removed. Welcome to visit vipprogrammer.com.

Posted by: FM WhatsApp APK at 5pm (CIVg6)

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