Is your iPhone XR keeps rebooting, especially when playing games? You’re not alone. This common issue often stems from overheating at the chip level, causing the device to trigger Apple panic codes and enter a reboot loop. In this tutorial, we’ll walk you through a professional-level solution: chip-level board repair involving CPU, NAND, EEPROM, and baseband CPU transfer. Whether you’re a repair shop, technician, or DIYer, this guide will help you understand the root cause and how to fix it permanently.
Detalles del dispositivo
Modelo: iPhone XR
Anunciado: September 12, 2018
Customer Faced iPhone XR Keeps Rebooting
A customer’s iPhone XR would crash while playing games and then enter a constant reboot loop. The device wasn’t dropped, water-damaged, or improperly charged—ruling out external physical causes.
Step 1: Observe the Boot Loop
The phone repeatedly shows the Apple logo but fails to boot into iOS. Occasionally, it enters the system after several failed attempts.
Step 2: Analyze Panic Logs
We check the panic-full logs in the system. One key entry stands out:
AppleSocHot
Hot Hot Hot...
This message indicates SoC (System on Chip) overheating, which causes the phone to reboot. This type of error often stems from internal chip failure rather than external factors.
Solution: Swap Encrypted Chips to Another Working Board
Due to the chip-level failure, a board swap with encrypted chip transfer is required. The following components need to be moved:
- CPU
- Chip NAND
- CPU de banda base
- EEPROM lógica
Proceso de reparación
1. Disassemble the iPhone and Remove the Motherboard
Open the phone and safely remove the motherboard.
2. Remove the Shielding Cover and Clean CPU
- Use a hot air gun to remove the shielding cover.
- Clean the thermal grease from the CPU.
3. Remove Black Glue & Detach the CPU
- Carefully remove the black glue surrounding the CPU.
- Reheat the area using a hot air gun.
- Gently insert a thin blade while heating until the CPU chip is removed.
⚠️ Caution: Do not blow away the nearby Logic EEPROM (U1401) when heating.
4. Clean and Resolder the CPU
- Clean the removed CPU and the board’s contact pads.
- Reball and solder the CPU to a new donor motherboard.
5. Resolder the Logic EEPROM
Once the CPU is soldered, install the EEPROM lógica back in place.
Power-On Test
Connect the reassembled motherboard to a Fuente de alimentación de CC and trigger the boot. A stable current jump to around 50mA indicates the CPU is functioning correctly.
Remaining Steps
- Remove and reball the Chip NAND y CPU de banda base from the original board.
- Solder them onto the new motherboard along with the already-transferred CPU and EEPROM.
Reballing and soldering steps are similar to the techniques taught in REWA’s Handwork Course.
Pruebas finales
Once all encrypted chips are swapped and the board cools down, reassemble the phone.
Resultados:
- All functions work normally.
- The phone no longer reboots.
- It runs games and videos smoothly for over 30 minutes with no crash or loop.
Conclusión:
An iPhone XR keeps rebooting while gaming is typically suffering from a chip-level fault, especially overheating related to the SoC. The key solution is swapping all critical encrypted chips—CPU, NAND, Baseband CPU, and EEPROM—to a healthy donor board. Though this process requires advanced soldering skills and professional tools, it’s a proven and permanent solution. For repair shops and experienced technicians, this guide offers a reliable path to restore full functionality to affected iPhones.
Herramientas y piezas utilizadas:
Herramientas:
- Pistola de aire caliente
- Thin blade
- Pinzas
- Fuente de alimentación de CC
- Soldador
- Microscope (recommended)
- Thermal grease cleaner
- Reballing station (optional but preferred)
Piezas:
- Donor iPhone XR motherboard
- Original iPhone XR CPU (encrypted)
- Original NAND chip
- Original Logic EEPROM (U1401)
- Original Baseband CPU
Technical Term Clarifications:
- AppleSocHot – A panic log error indicating SoC overheating.
- CPU (Central Processing Unit) – Main processor of the phone.
- Chip NAND – Memory storage chip that holds iOS and user data.
- Logic EEPROM (U1401) – Stores logic configuration data.
- CPU de banda base – Handles communication functions like cellular and WiFi.
- Reballing – Reapplying solder balls to a chip to prepare it for resoldering.
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