How can I fix my iPhone 13 restarting and overheating after the iOS 26.5 update?

Remote diagnostics is not as thorough as having diagnostics done at an Apple Store Genius Bar.

If I had to guess, I suspect the melted cable caused hidden damage that remote diagnostics missed. Apple will perform the diagnostics free and that way you’ll know what you’re up against.

Genius Bar Reservation and Apple Support Options - Apple

If it got hot enough to melt a component as you claim, have Apple inspect it. Do not turn it on. Go to this page to find your nearest Apple Authorized Service Provider (AASP) or Apple Authorized Distributor (AAD) --> https://locate.apple.com/country

How to make a Genius Bar appointment

1. Go to Genius Bar Reservation and Apple Support Options - Apple

2. Go to "Get hardware help".

3. Select your hardware and continue selecting options requiring replacing parts until you see "Bring in for Repair"

4. Sign in with your Apple ID

Once updated there is no going back. Anyway, your iPhone is damaged if what you say is correct.

I agree with Limnos. iPhones are designed to shut off before getting hot enough to damage critical internal components. If your iPhone got hot enough to melt a cable, it presents a serious personal health risk. It needs to be inspected by trained Apple technicians.

Turn off the device and store away from combustible materials. If you’re in the US, please call  1-800-MY-APPLE, or outside the US, consult the support articles below. In Canada, call 1-800-263-3394.

Contact Apple for support and service - Apple Support

Genius Bar Reservation and Apple Support Options - Apple

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CyberSam65 wrote:

The phone melted the cable at the port connection to the phone. Clearly the phone is overheating, what is Apple going to do about this as I've read many issues surrounding this update.

If the cable melted at the connection to the phone, that sounds to me like there is some hardware issue with the cable, phone, or charger. My iPhone 12 mini ran hotter, and seems to run down battery charges faster, after the update from iOS 18 to iOS 26 – but not anywhere to the degree it would take to melt a cable.

If iOS 26 had some really bad bug that caused iPhones to melt cables on a routine basis, I believe these forums would likely be full of complaints about that, specifically, and not complaints merely about phones running a bit hotter, or complaints about people not iiking UI changes such as "Liquid Glass".

As far as I can tell, they aren't, and there is no systemic "overheating to the point of melting cables" issue.

I think we should be able to go back to the previous version.

You cannot downgrade iOS or iPadOS, and Apple will not see your wishes here.

If you like, you can make a suggestion using the iPhone link on the Product Feedback - Apple page, but I believe that your chances of getting struck and killed by lightning are greater than the chances that Apple will ever allow downgrading.

That reeks of a serious hardware problem. Bad battery. Failed charging circuitry. A short circuit somewhere.

As stated, stop using it. Get it looked at.

CyberSam65 wrote:

I had Apple Test the phone online, and they said the phone is not showing any errors. The phone may not have melted the cable as I didn't notice that it was damaged. I just removed it from my bad and saw the damaged cable.

Phones shut down when they overheat that is part of their design.

The Phone still shuts down randomly, I have pared back the number of Apps that I use; they are all up to date. Still shut down multiple times yesterday. Still seeking a solution.

Please open the Settings App. Tap Battery. Tap Battery Health and let us know what it is. I suspect, since you're dealing with a phone which was released in 2021, 5 years ago now, that if the battery in your phone is the original battery, it likely was due for replacement some time ago. If the Battery Health is 80% or lower, you need to pay Apple to replace the battery now.

Here's a commonly seen reply when there is a possible safety issue, so this probably applies in your case too:

Thank you for participating in the Apple Support Communities.

We want to make sure you reach the right Apple team for help with your device. We recommend that you contact Apple Support directly. Depending on your region, you may be able to reach them here: Get Support.

Thank you for participating in the Apple Support Community.

We want to make sure you reach the right team for help with your device. We recommend that you contact Apple Support directly. Depending on your region, you may be able to reach them here: Get Support.

CyberSam65 wrote:

Local person, not Apple. When I spoke to the Apple person online, they quoted $700 to repair it. I can get a very decent refurbished phone for that. Additionally, I would like to note that the phone was working fine on iOS 26. The issues seem to coincide with the latest update.

OK. Then your phone has parts which are not authentic Apple Parts. Only Apple or Apple Authorized Service Providers have authentic Apple parts. And that means your phone is ineligible for service from Apple. I hope the restore you performed works for you long term. Apple won't touch your phone if it doesn't.

CyberSam65 wrote:

Battery health is 91%

TBH this phone had an issue when we got it. A speaker issue. We were going to return it. Then it was in a car accident and had multiple issues. I had the whole front replaced. I’ve just replaced the speaker this week because that was the original issue. It was working fine on iOS 26 but went completely nuts when it updated to 26.5.

I’ve just reset the phone again via recovery via my computer. Interestingly enough it’s now in iOs 26.5.2. But this time the update via the computer was successful.

I’m typing this message via the iPhone 13. So far so good. A clean install maybe what is needed but it wasn’t doing it. It now has updated via resetting. Hmm time will tell if this has worked.

Who exactly did the repairs on the phone? Apple or some other service center?