How to Fix a Phone That Keeps Restarting Randomly (iPhone & Android) | Reparation Tech

Posted on:

October 4, 2025

Is your phone restarting unexpectedly — sometimes during calls, sometimes in standby, or right in the middle of launching an app? It’s one of the most frustrating issues a smartphone user can face: you never know when your device will reboot. Whether it’s an iPhone or an Android, this problem can stem from software bugs, failing hardware, or a misbehaving app.

In this guide, you’ll get a complete, step-by-step walkthrough to diagnose and fix a phone that keeps restarting. I draw on official sources (e.g. Google’s support pages) and real-world repair experience, so you’re not just getting theory — you get strategies that work.

(If you have a device problem you can’t solve, ReparationTech offers repair services for iPhone, Android, tablet, and more — see our iPhone repair and Android repair pages.)

Disclaimer: This post is for informational purposes only. If your phone has an unknown hardware fault or is under warranty, consider consulting a professional technician. Use these steps at your own risk.

What Causes a Phone to Restart Randomly? (Overview)

Before jumping into fixes, it helps to understand why this happens. Broadly, random reboots fall into software issues or hardware issues (sometimes both).

1.1 Software / System / App Problems

Operating system bugs or instability: New OS versions sometimes introduce system-level bugs that trigger crashes or kernel panics.
Conflicting or buggy third-party apps: An app might be misbehaving (memory leak, going out of bounds, conflicting with system APIs).
Corrupted system files or updates gone wrong: Incomplete firmware updates or corrupted system files may make core modules unstable.
Full or nearly full storage: When your phone’s storage is nearly exhausted, the OS may fail to allocate temporary files, leading to crashes.
Cache, logs, or background data overload: Overflowing caches or corrupted logs can push the system into instability.
Malware or malicious software: Though rarer on iOS, Android has a broader threat surface; malware could cause system crashes or forced reboots.

Google’s official support advice for Android notes that a reboot or crash loop is often due to software issues, and they advise checking for updates, clearing storage, and updating apps. Google Help

1.2 Hardware / Electrical / Component Faults

Battery degradation: As battery health declines, voltage regulation suffers. When the system demands more power (e.g. during processing or screen usage), the battery can’t keep up, causing a sudden reboot.
Overheating / thermal irritation: Overheating forces the system to shut down or reboot to protect components.
Loose connectors or damaged flex cables: A loose solder, a cracked trace, or a partially broken ribbon cable (e.g. to the motherboard) can make the phone behave erratically.
Power IC or voltage regulator faults: Failures in the circuits that regulate power distribution can lead to random restarts.
Short circuits or water damage: Internal short circuits from moisture or damage can trigger resets.
Faulty buttons or housing pressure: If the power or volume buttons are being pressed inadvertently (by a warped case or debris), the phone may interpret it as a reboot command.

Many users on Apple’s discussion forums note that “panic” logs or frequent “panic” entries in analytics logs may hint at a hardware-level issue. Apple Support Community

1.3 Mixed Causes / Interactions

Often, the cause is not purely software or purely hardware. For example, a failing battery (hardware) might push the software to unstable states when the OS demands more current. Or an app with a memory leak (software) may stress the thermal/regulation hardware, triggering shutdowns.

Knowing this, the best approach is to systematically rule out causes from the easier (software) to the more complex (hardware).

Diagnostic Checklist — Work from Easy to Hard

Here’s a structured checklist you can follow. Always back up your data before making substantive changes.

Step	What You’ll Do	Why / What It Helps You Determine
2.1	Back up your data	Prevent data loss before you mess with system resets or hardware tests
2.2	Force reboot / safe-mode / boot options	Check if baseline OS is stable without third-party interference
2.3	Update OS & apps	Rule out known stability patches or app bugs
2.4	Free up storage & clear caches	Remove resource shortage as a cause
2.5	Remove suspicious apps or use safe mode	Isolate a misbehaving app
2.6	Check analytics logs / panic reports (iOS)	See if you’re getting repeat error logs
2.7	Check battery health & thermal conditions	See if battery or heat is the culprit
2.8	Check external accessories / case / ports	Sometimes cases or docks interfere
2.9	Factory reset / reinstall firmware	Start clean; if issue persists, hardware issue is likely
2.10	Professional diagnostic / hardware review	If all fails, time to consult a technician or repair service

Below, I’ll expand each of these steps — for both Android and iPhone — with precise instructions and caveats.

Practical Fixes for Android & iPhone

3.1 Back Up Your Data (First Thing)

Always start by backing up:

iPhone: Use iCloud or connect to a Mac/PC and back up via Finder (macOS) or iTunes (Windows).
Android: Use Google Drive backup, manufacturer’s backup tools (Samsung Cloud, Xiaomi’s MI Cloud, etc.), or manually copy photos, files, contacts.

You never know when a reset or hardware fix will erase your data, so protect it.

3.2 Force Reboot / Safe-Mode / Boot Options

iPhone

For iPhone 8 / X / newer: Press Volume Up → Volume Down → Press and hold the Side button until Apple logo.
For older iPhone models: Press and hold Home + Power until logo appears.
Note: iOS does not provide an official “Safe Mode” unless jailbroken.

If after a force reboot the phone is stable, it suggests a transient software glitch rather than deep hardware failure.

Android

Press and hold the power button until the power menu appears → Press and hold Power Off option → confirm “Reboot to Safe Mode”
In safe mode, third-party apps are disabled. If the phone stops restarting in safe mode, the cause is likely an app. Google’s support documentation even recommends this approach. Google Help
If issue still happens in safe mode, the problem likely lies deeper (OS or hardware).

3.3 Update OS & Apps

iPhone: Settings → General → Software Update → install any pending updates. Also update apps via the App Store.
Android: Settings → System (or About Phone) → System Update. Also open the Play Store → Manage apps & device → Update all pending apps.

New patches often contain stability fixes that address random reboot issues.

3.4 Free Up Storage, Clear Caches, Remove Junk

Delete old photos, videos, files, large downloads.
Uninstall apps you rarely use.
Clear app cache (Android) — Settings → Apps → [App] → Storage → Clear Cache / Clear Data.
For Android, wiping the system cache partition (if supported) is also beneficial.
On iPhone, removing unused apps and large attachments can reduce pressure.

If the system was failing due to resource starvation, this step often “unlocks” normal functioning.

3.5 Isolate / Remove Misbehaving Apps

In safe mode, if the system is stable, gradually re-enable apps.
Think about events prior to symptoms: did you recently install a new app?
Uninstall suspect apps.
You may also check system logs or crash reports (Android’s logcat or iOS’s analytics) to see if a particular app is referenced.

3.6 Check Analytics / Panic Logs (iOS)

On iOS: Settings → Privacy & Security → Analytics & Improvements → Analytics Data.
Scroll through the crash logs — if you see repeated entries named “panic” or referencing a particular subsystem, that may pinpoint where the crash is happening. Several users have found this helpful. Apple Support Community
If you see consistent hardware-level component references, it’s hinting at non-software error.

3.7 Check Battery Health & Thermal Conditions

iPhone: Settings → Battery → Battery Health & Charging. If the maximum capacity is significantly degraded (e.g. below ~80%), the battery is suspect.
Android: Use diagnostic tools (some phones have battery health menus) or third-party apps (e.g. AccuBattery) to check battery wear.
Monitor device temperature. If the phone feels hot when it reboots, it’s likely thermal or power stress.

If a failing battery struggles to supply stable voltage, the phone will reboot under load.

3.8 Inspect External Accessories, Ports, Cases

Remove cases, screen protectors, grips, battery packs or mounts — sometimes they press buttons or interfere with ports.
Blow out ports (charging / headphone) gently with compressed air and inspect for debris.
Faulty chargers or cables may cause power fluctuations that can trigger restarts. Try using a known good cable and charger.

3.9 Factory Reset / Firmware Reinstall

iPhone: Settings → General → Transfer or Reset → Erase All Content and Settings → then restore from a fresh backup.
Android: Settings → System → Reset Options → Erase all data (factory reset).
Alternatively, manually flash a fresh firmware (official ROM) using the manufacturer’s tool.
After reset, before re-installing all your apps, monitor the phone to see if it remains stable.

If after a clean OS install, it still restarts, the cause is almost certainly hardware.

3.10 Professional Diagnostic / Hardware Repair

Once software causes are eliminated:

Contact a professional repair technician. Services like ours at ReparationTech can diagnose battery, power IC, or motherboard faults.
Request a component-level diagnostic (battery, connectors, voltage rails).
If under warranty, contact the manufacturer or service center.
Be prepared that some repairs (motherboard replacement, power IC) may be costly.

You can explore our repair a device page to start a repair request.

Detailed Tips & Advanced Considerations

Here are deeper tips and caveats based on real-world experience.

4.1 Use Minimal Load to Test

After a reset or fix, run the phone with minimal apps (no third-party app, no widgets) for some hours. See if it restarts. Then incrementally add apps until instability returns — that helps you narrow the culprit.

4.2 Monitor Crash / System Logs

On Android: use adb logcat (from PC) to monitor system logs in real time, ideally capturing the moment before reboot.
On iPhone: use analytics logs (as earlier) or connect to a Mac and use Console to view crash logs.

These logs often reveal error codes or component names triggering the crash.

4.3 Avoid Overheating

Don’t use high-intensity apps (e.g. games, video editing) for extended periods, especially in hot weather.
Avoid charging while using heavy tasks.
Use original or high-quality chargers to avoid overvoltage/undervoltage.
If the phone is physically hot before reboot, cooling or replacing thermal interface / shielding may be needed.

4.4 Beware of Non-Official Firmware / Root / Jailbreak

If your phone is rooted (Android) or jailbroken (iPhone), system stability is more fragile. Unintended modifications may trigger reboot loops.
If possible, restore to stock firmware and unroot/un-jailbreak to see if the issue goes away.

4.5 Be Mindful of Aging Components

If your phone is older (3–4+ years), battery and power circuits naturally degrade. Replacing the battery may resolve many random restarts.
Capacitors or solder joints may fatigue. Mechanical stress or drops may cause hairline fractures. A technician’s microscope inspection often helps.

4.6 Reevaluate After Each Change

Always test after each fix you apply. Don’t do everything at once — it makes isolating the cause harder.

iPhone-Specific vs Android-Specific Tips

Here are some platform-specific insights to help you further.

iPhone (iOS) Tips

Keep Automatic Updates enabled (Settings → General → Software Update → Automatic Updates).
Reset Network Settings (Settings → General → Transfer or Reset → Reset → Reset Network Settings) — sometimes network stack issues cause system instability.
Use DFU mode restore (Device Firmware Update) if a normal restore doesn’t fix it. This is a low-level reinstallation of iOS.
If you see repeated panic logs in Analytics Data, take note — Apple technicians use these.
Avoid repeated fast battery drains or exposing the phone to extreme cold/heat.

Android Tips

Use Wipe Cache Partition (in recovery mode, if supported) to clear outdated system cache.
On Samsung phones: check Device Care → Auto optimization, make sure periodic optimization doesn’t trigger reboots. Some users report toggling off these features helps. Samsung Community
For devices using manufacturer custom skins (One UI, MIUI, etc.), be wary of aggressive optimization or battery-saving modes that kill background processes too aggressively.
Use safe mode as your first diagnostic. Google Help
If your device supports it, monitor battery current / voltage via hidden diagnostic menus or apps to see if the battery behaves erratically under load.

A Sample Walkthrough (Case Study)

Let me walk you through a hypothetical but realistic example:

Symptom: A user’s Android phone randomly reboots twice a day, often while browsing or after taking photos.

Steps they took:

Backed up data.
Rebooted into safe mode. Reboots ceased — pointing to a third-party app.
Uninstalled recently added apps. One camera-enhancement app was suspect; removal improved stability.
Cleared storage (deleted large video files) and cleared app caches.
Updated system and apps.
Ran for 24 hours with minimal apps — still stable.
Reintroduced apps gradually; instability returned when “Photo Editor X” was installed. Removed it permanently.
Monitored battery behavior — battery voltage stayed stable under load, so battery seemed okay.
Tested in normal mode — stable.

Conclusion: A buggy third-party app was the culprit.

In another case, a user’s iPhone 11 kept rebooting. They:

Saw multiple “panic” logs in Analytics → hardware suspicion
Replaced battery via service center
Reboot issue stopped entirely

Thus, diagnosing carefully saved them from needless reinstalling or buying a new phone.

When to Give Up and Seek Professional Help

If you’ve exhausted all of the above, these are signs you should stop and call a technician:

The phone reboots even in safe mode or right after a factory reset.
You notice battery bulging, rapid heating, or swelling.
The cost / complexity of repair (motherboard, power IC) is beyond your comfort.
The phone is under warranty — you don’t want to void it by opening the device.
Visual damage: moisture/humidity, water ingress, or physical drops.

At ReparationTech, we handle iPhone, Android, tablet, Apple Watch, and more. You can submit a device repair request via our repair a device page, or explore our tablet repair and computer repair services too.

You can also check out our location page to see if there is a branch near you, or read about us on our about us page.

Summary & Final Thoughts

Random reboots are frustrating, but often stem from manageable software causes — always start there.
Follow a structured diagnostic approach: backup → safe mode → update → clean → isolate app → reset → hardware.
System logs, battery data, and behavior in safe mode are your best clues.
If all fails, don’t hesitate to bring the device to a qualified technician.

Phones are complex devices, and sometimes even experts need specialized tools to trace hardware faults. But many reboot loops can be resolved at home if you proceed methodically.

I hope this guide helps you get your phone stable again. If you need assistance with repairs or diagnostics, feel free to reach out via our repair a device page.

FAQs

Q1: Why does my phone restart only when I open a specific app?
A1: That indicates the app is likely causing a crash — either due to memory overuse, incompatibility, or bug. Uninstall or update that app first.

Q2: I replaced the battery but the phone still reboots — what next?
A2: The issue may lie in the power circuitry (voltage regulators, connectors) or motherboard. Time for professional diagnostics.

Q3: Will rooting or jailbreaking cause random restarts?
A3: Yes — modifying the system increases instability. If possible, revert to stock firmware and test again.

Q4: Can a software update ever make this worse?
A4: Sometimes, yes. A buggy update or an incomplete installation can introduce new errors. In that case, restoring to a stable version may help.