View source for IPhone 12 Stuck on the Apple Logo Error 4013 Repair

{{Repair Guide
|Device=IPhone 12, IPhone 12 Pro, IPhone 12 Pro Max, IPhone 12 Mini
|Affects parts=Motherboard
|Needs equipment=screwdrivers, spudger
|Type=Part replacement
|Difficulty=1. Easy
}}
{{stub}}

==Problem description==
Diagnosis and repair of an iPhone 12 that boot loops and only shows the Apple logo on screen.
[[File:Placeholder image.jpg|thumb|Example image (Figure 1) -- No image yet. Help expand this page by uploading it!]]
==Symptoms==

*Shows Apple logo for about 5 seconds, then blank, then Apple logo, then blank.
*Sometimes it shows a green flash for a second.
*If you try to flash an update or restore, it fails right away with an Error 4013.
*If you flash on 3U Tools, it fails at 19%.

==Solution==
Flex Cables:

* Step 1 in this case is always unplug all the flex cables.
* Ideally test the board with known good screen, battery & charging port.
* If it boots, then one of your flexes is the cause.
** 99% of the time, it is the ear speaker flex. The flood illuminator and/or the ALS has liquid damage.
** The ear speaker flex is paired to the logic board for Face ID.
** If you want to keep Face ID, you'll need to repair the flex. If Face ID is not important, then you can just replace the flex.
*** To repair the flex, you'll have to desolder the component & clean out all the corrosion, then place them back.
*** If the corrosion is too severe & it damaged the flex, then you'll need to swap the flood illuminator and ALS to a new flex, otherwise, you'll lose Face ID.
** In some cases, another flex can cause this issue like a bad charging port.
*** In this case, just replace the flex

Please Note: If the phone is stuck in Recovery Mode because it failed at the Error 4013, you have 2 options

# Kick the device out of Recovery Mode using 3U Tools. In the main screen of 3U Tools, you'll see a button that says "Exit Recovery Mode"
# You can attempt another update or restore.