Fix “Accessory Not Supported” Message on iPhone — Real Causes and How to Solve It
iPhone shows “Accessory Not Supported” for many reasons — cable fault, port issue, voltage drop, or even a board-level fault. Here’s a clean guide based on real repair cases.
High Demand & Real Customer Cases
Our shops in Christchurch and Auckland see more than 10–20 cases every week. Customers are confused because the cable works one moment and fails the next.
What Customers Usually Experience
- Charging stops randomly with the error message.
- Works only in some places (car, home, office).
- “Looks” like a genuine cable but fails handshake.
- Multiple cables tried, same failure.
Real Repair Cases from Our Shops
- Dust blocking lightning pins → handshake failure.
- Car chargers causing unstable voltage.
- Corroded lightning socket → board-level inspection needed.
- Fake “genuine” cables with dead MFi chip.
Technical Breakdown (For Experts)
MFi chip (C89/C94) manages encrypted handshake with iOS. If the chip fails, the phone instantly rejects the connection. Voltage fluctuations under 5V also trigger the alert. Severe cases relate to U2/Tristar IC damage.
How to Fix It
- Clean the lightning port carefully (wooden toothpick only).
- Test with genuine or MFi-certified cable.
- Use a wall charger instead of car chargers for testing.
- Restart the phone and update iOS.
- Check “USB Accessories” toggle in Settings.
- Port cleaning or replacement if corrosion is found.
- Board repair if U2/Tristar IC is damaged.
If the issue keeps happening, bring it to EziRepair in Christchurch (03 343 1078) or Auckland (09 392 0039). We diagnose cable, port, and board-level faults.