We got the iPhone 6 plus from one of our customers, he dropped it last month then cannot turned on it after using for few days. As she said, there is no important information and activation lock. so we root it and find that unknown error (9) reported on it. How to solve this problem? Let's take a look step by step.
Use iTunes (or i4) assistance to root and it reports unknown error (9).
First remove NAND FLASH and measure the diode data to ground, finding them normal. I suppose that the NAND FLASH itself is damaged. After I replacing a new one, the problem remains the same, so NAND FLASH is excluded.
Next I check CPU. Customer said that it has been dropped. As for dropped iPhone 6 or iPhone 6 Plus, the solder pad that CPU uses it to connect logic eeprom chip is easy to drop joints. Remove logic chip to measure the diode data. The location of logic chip is shown in the following picture.
Then I measure the diode data to ground of the solder pad, finding that the data is infinite. Thus, I can be sure that CPU is pseudo soldering. After removing CPU, I find that the some of CPU pins connected with logic chip are gone, as shown in the picture.
After fixing the upper and lower board of CPU, jump two wires from solder pad to logic board. The picture of soldered CPU is not clear, but I can see the jumped wires and UV Solder Resist, as shown in the picture.
After jumping wires and soldering CPU, turn iPhone on and get into IOS, as shown in the following picture. I have to explain specially that the screen in the picture is the testing screen that we use during repair process. It is a little blurred, which has nothing to do with motherboard.
Good luck to your cell phone repairs. More phone repair skills read at www.vipfixphone.com
Judging from my experience, NAND FLASH or CPU problems could cause the error (9).
First remove NAND FLASH and measure the diode data to ground, finding them normal. I suppose that the NAND FLASH itself is damaged. After I replacing a new one, the problem remains the same, so NAND FLASH is excluded.
Then I measure the diode data to ground of the solder pad, finding that the data is infinite. Thus, I can be sure that CPU is pseudo soldering. After removing CPU, I find that the some of CPU pins connected with logic chip are gone, as shown in the picture.
After jumping wires and soldering CPU, turn iPhone on and get into IOS, as shown in the following picture. I have to explain specially that the screen in the picture is the testing screen that we use during repair process. It is a little blurred, which has nothing to do with motherboard.
Good luck to your cell phone repairs. More phone repair skills read at www.vipfixphone.com
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