How To Fix iPhone 4S That Is Bootlooping With iTunes Error 29

How To Fix iPhone 4S That Is Bootlooping With iTunes Error 29
Device	iPhone 4S
Affects part(s)	Main Logic Board
Needs equipment	Soldering Iron, Hot Air Station, Insulated Jumper Wire
Difficulty	◉◌◌◌ Easy
Type	Soldering

Problem description

If the iPhone 4S is Bootloopin and you flash an update that causes Error 29 (failing at 60% with iTunes flash)

Or 3u Tools Easy Flash failing at 80% (Updating GasGauge).

Then follow these steps to resolve it

Figure 1. iPhone 4S battery connector area. Shows how R61 is missing due to liquid damage causing the filter to go missing.

Symptoms

• Bootlooping
• Flashing Apple Logo
• Restarting with the Apple Logo Flashing
• Failing an update with error 29
• Failing at about 60% on iTunes flash
• Failing at 80% on 3u tools with the message "Updating GasGauge"

Solution

Diagnostic Steps

• This is often caused by a low-quality replacement battery, use an original battery.
• Check for missing components near the battery connector. See Figure 1.

Figure 2. Here is a temporary solution on iPhone 4S that had a missing R61 filter. This is for data recovery only.

Repair Steps

• A missing R61 resistor near the battery connector can cause this. Replace it.
• For data only, you can also try running a jumper across the pads, to recreate the connection. See Figure 2.