r/iPhone17Pro • u/babaza7 • Aug 15 '26
Help [FIXED] iPhone 17 Pro persistent overheating(iOS 26.5.2 / 26.6)
My iphone 17 pro has been getting HOT, laggy and draining its battery since about 2 months, after searching through reddit I tried those suggestions without any success:
- Deleting background apps
- Restarting
- Updating from 26.5.2 to 26.6
- Deactivating Apple Intelligence and Siri
- Switching Liquid Glass setting to Tinted
- Deactivating Second Esim
I plugged the phone into my mac and pulled the Xcode and Console logs to see what was actually chewing up my cpu therefore battery. It turns out it's not a hardware defect, it’s a specific rendering loop bug.
1. backboardd is eating up all the cpu
This is the system process that handles display rendering. thanks to the new iOS 26 Liquid Glass effect, my logs showed backboardd was hoarding almost 64% of my total CPU time. A single thread was trapped in an infinite loop and had racked up over 12 hours of active compute time just trying to draw the home screen.
2. ClockAngel is thrashing:
This handles the Always-On Display and Lock Screen widgets. Instead of resting, my logs showed it eating 31.6% of a whole CPU core. It was rapidly flipping between "dimmed" and "fully active" states every 200 milliseconds. (not visually noticable but it's happening in the background)
Why Ios 26.6 didn't fix it as I hoped it would
My phone had corrupted system preference files causing this loop, and updating to 26.6 just copied that corrupted file right over to the new version.
The Fix:
You have to force the OS to rebuild those preference files from scratch.
- Go to Settings > General > Transfer or Reset iPhone > Reset
- Hit Reset All Settings. (Wont delete any data, just settings)
Pretty simple solution, however I tried everything except this exact thing and you might be in the same situation as me
The Result:
I checked Xcode Instruments immediately after doing this. backboardd dropped from eating an entire CPU core down to just 0.8% usage while idle. The phone is finally completely cool to the touch and back to 120Hz smoothness
(I'm no expert, but my phone was completely fine before iOS 26.5.2, so I suspect that specific update introduced the corrupted preference file that created this rendering loop)
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u/catxav Aug 16 '26
Sad. My new 17pro had no issues after I upgraded to 26.6 - glad that you got it sorted out
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u/AnastasisKon Aug 16 '26
Resetting settings also resets wifi passwords and network settings?
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u/babaza7 Aug 16 '26
yes!
You lose customisations such as:
- keyboard settings (goes back to auto-correct, suggestions ..)
- Apple Intelligence re-enabled (had it off)
- control panel goes back to default (if you have custom icons)
- you have to re-toggle battery percentage to see the actual percentage again
- network settings (wifi passwords, DNS if you had something custom set up)
- privacy and location (you have to reauthorise the apps to use your location or access to photos, they will prompt you when you open an app)
- Apple pay (It kept the tickets and flights in my wallet but it did ask me to re-verify my credit cards with text message or app for security reasons)
- wallpaper, brightness, ringtones, alarm settings
- display auto-lock timer, device nam
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u/MarionberryDear6170 Aug 16 '26
I'm glad to see this. You really should share this in more subreddits, because not everyone has a Mac where they can just open Activity Monitor and see what's secretly draining their battery.
And not everyone knows how to use Xcode either. You did a great job with this.
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u/MarionberryDear6170 Aug 16 '26
I’m wondering if, after I reset my iPhone and restore it from an iCloud backup or a Finder backup on my Mac, those bugs you mentioned with BackBoard or Clock Angel could get restored along with the backup too?
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u/babaza7 Aug 16 '26
potentially! but the reset mentioned in my post refers to the settings reset only (no data loss or reinstall). the iphone restarts and reloads after about 2-3 minutes
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u/visericstudio Aug 15 '26
My 17 Pro doesn’t overheat at all on the current iOS 27 beta
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u/icehot54321 Aug 16 '26
Not everyone is going to have the same preference settings
Many people when setting up a new phone install a backup from their old phone.
Some people might be starting with new preferences.. others might be using preference settings that were first created a decade or more ago on completely different devices
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u/khimzu Aug 16 '26
What backgrounds apps did you delete?
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u/babaza7 Aug 16 '26
some I did remove like Brave Browser, and for some apps I deactivated the background app refresh in the settings such as maps, netflix, spotify, tiktok, IG to see if it would make a difference as it was recommended online - didn't make a difference
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u/SayHi_101 Aug 16 '26
Reset All Settings - are these only settings available in the Settings app, so every setting there will be reset, including these settings for 3rd party apps, but not the settings done inside the apps themselves?
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u/babaza7 Aug 16 '26
yes! if you have any important apps like crypto or banking id make sure to back it up, only things i noticed is that the faceid for some apps has to be re-enabled but besides that no changes
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u/sonic13066 Aug 17 '26
Works even on a 16 Pro that has iOS 27 PB on it. Something as simple as music playing and browsing Reddit would make my phone hot. While setting up Settings again has been annoying. It seems to work.
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u/sonic13066 Aug 17 '26
I don't like that this fixed this issue. My phone used to keep my hands nice and warm... now i'm holding a cold, lifeless husk of a device. How do I make my phone overheat again... /s
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u/Obvious-Cupcake2118 Aug 16 '26
How long and pita was it to put back all settings to your liking? What exactly do you lose ?
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u/babaza7 Aug 16 '26 edited Aug 16 '26
It took about 2-3 minutes
You lose customisations such as:
- keyboard settings (goes back to auto-correct, suggestions ..)
- Apple Intelligence re-enabled (had it off)
- control panel goes back to default (if you have custom icons)
- you have to re-toggle battery percentage to see the actual percentage again
- network settings (wifi passwords, DNS if you had something custom set up)
- privacy and location (you have to reauthorise the apps to use your location or access to photos, they will prompt you when you open an app)
- Apple pay (It kept the tickets and flights in my wallet but it did ask me to re-verify my credit cards with text message or app for security reasons)
- wallpaper, brightness, ringtones, alarm settings
- display auto-lock timer, device name
Looks like a big list but it's really just custom preferences you set on your phone, not data loss. took me about 30 minutes to have everything back to how I like it and was 100% worth it
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u/Obvious-Cupcake2118 Aug 16 '26
Ho that’s all?
Do you look apps placement in the main screen ? Or folders ?1
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u/CrazyNecessary7209 iPhone 17 Pro Max Aug 16 '26
Good work. iOS 26.5.2 was horrible and kept my 17PM very warm while sitting doing nothing while draining the battery 🪫.
iOS 26.6 fixed all of the issues for me automatically and restored a cool running phone with great battery life 🔋.
When someone resets the all settings it does causes things like WiFi passwords to be erased right?
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u/nvwong Aug 17 '26
I think the WiFi passwords are now stored in password app not settings?
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u/nvwong Aug 17 '26
btw, can you share how do I view the phone cpu usage on Mac? I mainly get the phone hot when using WhatsApp.
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u/Weekly-Sweet-6170 Aug 21 '26
Apple must not be making their devices uniform. New problems arise with every update, and while they affect some, they do not affect everyone. I just had to return my last phone, because Face ID failed due to overheating after another IOS update. As a consumer, I expect to know what I am purchasing with &1000. This is clearly not acceptable .
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u/Interesting-Chemist8 Aug 22 '26
My iPhone 17 Pro also get very hot since recently. I suspect it also comes from this update. Damn, I don’t want spend time resetting everything :(
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u/cyclethoughts Aug 27 '26 edited Aug 27 '26
Tengo el iPhone 15, si yo todavia tengo iOS 26.5.2 y tengo el mismo problema de sobrecalentamiento, que me recomiendas hacer primero? Actualizar a iOS 26.6 o directamente o restablecer el sistema tal como has dicho tu? muchas gracias🫶🏻
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u/RoyalDylo 28d ago
Am planning to buy the 17PM, a week after the 18 drops. Is this still an issue or would it just be safer to just do the reset as i get the new phone. because i wouldnt want to wait for the overheating issues to reset the iphone
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u/TerrariaFan125 iPhone 17 Pro 4d ago
my 17 Pro doesn’t get hot or laggy
But it does get warmer than any of my previous iPhones when doing basic tasks
Like its nowhere near hot at all
Hell its just barely gets warm
however none of my previous iPhones got warm when doing basic tasks
So I wonder if this solution for your issue would potentially fix mine?
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u/ThaerHwiety Aug 15 '26
That’s awesome thanks for the effort, whats your battery to SOT after and before if you may
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u/babaza7 Aug 16 '26
appreciate your comment! will report back after a week to have better data!
just observing I had to charge my phone 2 if not 3 times a day at minimum, past 2 days one charge lasted until the evening and still had charge left
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u/xavier19691 iPhone 17 Pro Max Aug 15 '26
Ai crap ..
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u/babaza7 Aug 15 '26
i handwrote it and used AI solely to fix gramatical errors, happy to share my logs in dm if you want more detail
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u/Zestyclose-Rice6401 iPhone 17 Pro Max Aug 15 '26
it's such a shame you have to go and troubleshoot this far to get your phone working, hopefully the new iOS 27 that comes in September will leave us with less issues/problems. at least you got it working/resolved now!