Why is my iPhone 6S stuck on the Apple logo, and what could be the causes?

Here’s what might be going on:

1. Corrupted Update: If you tried to update your iPhone, the update might have been corrupt or incomplete.
2. Failed Jailbreak: Jailbreaking your iPhone can override many security features; if something went wrong during the jailbreak, this could cause boot issues.
3. Faulty Apps: Sometimes, apps not compatible with your iOS version or malfunctioning ones might interrupt the startup routine.

Here are a few factors that I believe could cause this problem:

1. Software Issues: Your iPhone’s software might have encountered a glitch. It can happen during a software update or installation where the process didn’t complete correctly or has been corrupted.

2. Hardware Damage: Issues with the internal components, possibly due to a drop or water exposure, can cause your iPhone to fail to boot properly.

3. Jailbreak: If you’ve attempted to jailbreak your device, it might have not been done correctly, which can cause the phone to get stuck.

4. Full Storage: Your iPhone may have no available memory left, preventing it from starting up as usual.

You might want to consider these detailed factors:

1. System Crashes: Sometimes, iPhones get stuck if the operating system encounters a critical error and crashes. This could result from software bugs or corrupted files.

2. Update Issues: If the iPhone 6S gets stuck on the Apple logo after an update, the update likely failed or corrupted. Updates from iTunes or OTA (Over the Air) might sometimes not install correctly if the connection interrupts or the package is incomplete.

3. Beta Software: Running beta iOS versions is also risky, and bugs in these versions can prevent your phone from booting correctly.

4. Malware: Although rare, malware can affect iPhones, mainly if the device has been jailbroken. Malicious software can interfere with normal operations, including the boot process.

5. Connection Problems: If the phone stays on the Apple logo during a restore from iTunes, it could indicate a problem with the connection or the backup being restored.

Let’s dive into some step-by-step troubleshooting:

1. Perform a Hard Reset:
2. Press and hold the Power (Sleep/Wake) button and the Home button simultaneously.
3. Keep holding these buttons for at least 10 seconds.

4. Release them once you see the Apple logo reappear.

5. Put Your iPhone in Recovery Mode:

6. Connect your iPhone to a computer with iTunes.
7. Perform a hard reset as described above, but keep holding the buttons even after the Apple logo appears.
8. Release the buttons when you see the recovery mode screen.

9. Follow the on-screen instructions in iTunes to restore your device.

10. Use DFU Mode:

11. Connect your iPhone to your computer.
12. Quickly press and release the Volume Up button, then the Volume Down button.
13. Press and hold the Side button until the screen goes black, then immediately press both the Side button and Volume Down button.
14. After 5 seconds, release the Side button but keep holding the Volume Down button until iTunes recognizes it in DFU mode.
15. Restore the device in iTunes.

From my expertise, addressing the following could resolve the issue:

1. Update Problems: Updates failing or interrupted can cause the phone to stick on the Apple logo. Ensure the update process completes without interruptions, using a stable network.

2. Backup Issues: Sometimes, restoring from iCloud or iTunes backup may bring along corrupted settings or data. Avoid restoring and freshly set up the iPhone.

3. Check Connections: If restoring via iTunes, ensure the Lightning cable is connected correctly and is not damaged.

4. Safe Mode: Boot the phone into safe mode to see if a third-party app might be causing the issue.