Have you experienced boot failure after dropping the iPhone 12 Pro? Drop damage is one of the most common causes of boot failure in smartphones. In this repair guide, we’ll walk you through the complete process of reviving a severely damaged iPhone 12 Pro that won’t boot due to a fractured double-layer motherboard. Moreover, we’ll show you how to recover lost data by swapping encrypted chips onto a donor board, such as irreplaceable photos. Whether you’re a professional repair technician or a DIY enthusiast, this article provides a deep look into advanced logic board repair methods.
Phone Overview
Model: iPhone 12 Pro
Announced: 2020, October 13
Damage Inspection:
After the drop, the iPhone 12 Pro showed a cracked screen and back glass. More concerning iPhone 12 Pro boot failure. The customer urgently needed to recover important photos from the device.
Diagnostic initial :
Upon disassembling the phone, it became clear the double-layer motherboard was nearly separated due to the impact.
- Removed the protective sticker on the NAND chip – visually intact.
- Heated the board using a hot air gun and heating platform to carefully separate the two layers.
Chip Condition Check:
- After separation, both the NAND chip and CPU appeared undamaged.
- However, internal damage was found in the logic board’s rail area, indicating the board was structurally broken and beyond full restoration.
Chip Swapping Process for Data Recovery:
Considering that the board inside the rails is cracked and broken, the data recovery can be accomplished by swapping out the encrypted chip for a different one.
The first step is to carefully remove the NAND chip and CPU.
Remove the glue from the CPU pads, then clean them and reball them
Also, clean the pads on the NAND chip and reball it using the stencil, solder paste, and hot air gun.
We have now prepared the two most important chips.
- Solder the CPU onto the new motherboard
- Swapping the Logic EEPROM (stores calibration/configuration data).
Trigger Current Test:
- Tested the board without the NAND chip installed.
- Read a trigger current of 80mA, which is consistent with normal DFU mode—good sign.
NAND Installation & Boot Test:
- Soldered the NAND chip back onto the new board.
- Assembled and tested the device. Still wouldn’t boot.
- Suspected dock flex cable damage. Re-tested the board by connecting only the battery and screen.
✅ The iPhone booted successfully.
Signal Board Repairs:
- Reballed and reinstalled the Baseband CPU et Wi-Fi chip onto the baseband layer.
- Cleaned the frame pads and rebonded the two motherboard layers together.
Final Testing:
After reassembling the iPhone 12 Pro:
- All functions tested and passed.
- Only the screen needed replacement.
- The phone was successfully restored—full data recovery and operational. A true “full blood resurrection”.
Outils et pièces utilisés :
Outils :
- Pistolet à air chaud
- Heating platform
- Fer à souder
- Stencil for reballing
- Pâte à braser
- Pince à épiler
- Microscope
- Flux
- Logic board holder
- Cleaning solution (e.g., isopropyl alcohol)
Pièces détachées :
- iPhone 12 Pro motherboard
- Replacement screen
- Dock flex cable (if damaged)
- Thermal pads (if needed)
Technical Terms:
- Double-layer motherboard: The iPhone 12 Pro’s logic board consists of two layers soldered together, one handling signal processing (logic layer) and the other handling power and RF signals (baseband layer).
- NAND chip: The flash storage chip that contains user data such as photos and apps.
- CPU (Central Processing Unit): The phone’s main processing chip. In iPhones, it contains encrypted data tied to the NAND.
- Reballing: A process where you apply new solder balls to a chip to allow it to be soldered onto another board.
- DFU Mode (Device Firmware Update): A recovery mode that allows communication between the phone and a computer even when the phone isn’t booting normally.
- Baseband CPU: Controls cellular communication. It must be matched and reballed if swapped.
Conclusion :
Physical damage doesn’t always mean the end for your iPhone 12 Pro—especially if important data is at stake. With advanced microsoldering skills and the right tools, it’s possible to swap critical encrypted chips like the CPU and NAND onto a new motherboard, recovering full functionality and preserving user data. For professionals and skilled DIYers, this repair highlights the importance of precision, patience, and a strong understanding of iPhone logic board architecture.
English 
Español 
Français 
Deutsch 
Italiano