• Skip to main content
  • Skip to primary sidebar
  • Home
    • About
    • Contact
  • How-to
    • Android 12 update vs One UI 4.0 vs One UI 4.1: update Galaxy S21, S20 and S10 to Android 12
      • Top 12 new features in Android 12 update for Galaxy S21, S20 and S10
      • How to use Extra Dim on Galaxy S22, S21, S20, and S10? How to use Extra Dim on Galaxy S22, S21, S20, and S10?
      • Should I enable Protect Battery to limit the maximum battery charge to 85% on Galaxy S22, S21, S20, and S10?
      • Do You Need to Enable the Suspend Execution for Cached Apps on Galaxy S22 or Galaxy S21, S20, and S10 with Android 12 update?
      • How to Automatically Convert a Photo to a Time-lapse video with Scene Relighting on Galaxy S22, S21, S20, and S10?
      • A complete guide for Writing Assistant on Samsung Keyboard on Galaxy S22, S21, S20 and S10 (with Android 12)
    • How to charge Galaxy S21 battery properly?
    • Ultimate Guide for Using SIM Card on Galaxy S21
    • Master Meaning of Galaxy S21 Status Icons and Notification Icons
    • Layout of Galaxy S21, S21+, and S21 Ultra
      • How to Use and Customize Galaxy S21 Side Key?
      • How to use Galaxy S21 quick settings panel?
      • How to use touchscreen gestures on Galaxy S21?
      • How to power on, power off, and reboot Galaxy S21,even when the phone hangs?
      • How to migrate to Galaxy S21 with Samsung Smart Switch?
    • Understand and Use Galaxy S21 Lock Screen
      • How to lock Galaxy S21 screen?
      • Master Galaxy S21 Lock Screen Settings
    • How to Use Galaxy S21 Home Screen?
      • How to use widgets on Galaxy S21?
      • How to Customize Galaxy S21 Home Screen?
      • How to use LED icon editor to customize LED icons for Smart LED View Cover and LED Back Cover?
    • How to use and customize Galaxy S21 navigation buttons and navigation bar?
      • How to use navigation gestures on Galaxy S21?
      • How to use NavStar (Good Lock) to customize navigation buttons and navigation bar on Samsung Galaxy phones?
  • New Features
    • Top 13 new features in One UI 5 update (Android 13 update) for Galaxy S22, S21, and S20
    • Android 12 update vs One UI 4.0 vs One UI 4.1: update Galaxy S21, S20 and S10 to Android 12
    • Master Google Discover and Samsung Free on Galaxy S21
    • Top 6 disappointments of Galaxy S21 Ultra
    • Galaxy S21 vs Galaxy S21+ vs Galaxy S21 Ultra
  • Camera
    • How to use Galaxy S21 Camera App?
    • How to Use Galaxy S21 Camera Modes?
    • Ultimate Guide for Galaxy S21 Camera Settings
    • How to use Galaxy S21 camera quick launch?
    • How to set and resize photo size on Samsung Galaxy S21, S20, S10, and S9 without using any third-party apps?
  • Accessories
    • How to use Galaxy S21 Smart Clear View Cover (S-View Flip Cover)?
    • How to Use Galaxy S21 Smart LED View Cover (LED Wallet Cover)?
    • How to use LED icon editor to customize LED icons for Smart LED View Cover and LED Back Cover?
  • User Manual
Samsung Galaxy S21 Guides

Samsung Galaxy S21 Guides

How to power on, power off, and reboot Galaxy S21,even when the phone hangs?

Last updated on: October 15, 2021

power on, power off, and reboot Galaxy S21,even when the phone hangsYou need to power on, power off, or reboot Galaxy S21 once in a while. Sometimes, you may have to reboot Galaxy S21 without accessing the power-off menu if the phone hangs.

This Galaxy S21 how-to guide explains how to power on, power off, and reboot Galaxy S21 even if the phone hangs and how to access the power-off menu.

In this guide, Galaxy S21 refers to all Galaxy S21 models, including Galaxy S21, S21+, and S21 Ultra. The features discussed in this guide are common on all these Galaxy S21 phones.

Contents hide
1. Why and when do you need to power on, power off, and reboot Galaxy S21?
2. What is Galaxy S21 Power-off menu?
3. How to power on Galaxy S21?
4. How to power off Galaxy S21
5. How to reboot Galaxy S21?

Why and when do you need to power on, power off, and reboot Galaxy S21?

To set up Galaxy S21 or migrate from an old phone to Galaxy S21, you have to power on the phone first.

It is a dead brick when it is powered off. So, you need to keep it on if you want to use your Galaxy S21.

Sometimes, you may need to power off Galaxy S21. For example, when you enter some sensitive locations, you may be asked to power off the phone and lock it in the locker.  On the aeroplane, during taxing and landing, normally, you are asked to power off the phone, although it is not enforced strictly nowadays.

So, you need to power off Galaxy S21 when you are not allowed to use the phone or when you do not want to use the phone for an extended period.

Please note, if the battery level is too low, Galaxy S21 will power off itself automatically. You have to charge Galaxy S21 battery before you can power it on.

Reboot Galaxy S21 (aka restarting Galaxy S21) is required when you update the firmware (e.g., monthly security update). In this case, when you choose to install the update, Galaxy S21 will reboot automatically. Some updates may reboot Galaxy S21 more than once.

You may have to reboot Galaxy S21 if you change the SIM card, or activate a new eSIM profile.

Samsung also recommends you reboot Galaxy S21 at least once a month to “clean up” the system. You can set it up to reboot Galaxy S21 automatically at a specific time.

Occasionally, you may want to restart Galaxy S21 manually when you feel the phone is less responsive or behaves weirdly.

What is Galaxy S21 Power-off menu?

In old smartphones, there is a dedicated power button. Over the years, smartphone manufacturers added more and more functions to the power button.

On Galaxy S21, there is no power button. Instead. Galaxy S21 uses the Side key (right to the phone) to power on the phone.

As explained in this guide, by default, you can press and hold (long press) the side key for 2-5 seconds to get the power-off menu, as shown in the screenshot below.

power off Galaxy S21 or reboot Galaxy S21 through Galaxy S21 Power-off menu

Galaxy S21 power-off menu allows you to:

  • Power off Galaxy S21.
  • Restart/reboot Galaxy S21.
  • Lockdown Galaxy S21.
  • Turn on Emergency mode.
  • Quick access to Side key settings.

Please note, Samsung allows you to assign the long-press gesture of the Side key to Bixby Voice.   In this case, you can access the Galaxy S21 Power-off menu from the quick settings panel. You can also use the Side key to launch the camera app quickly.

You can call out the power-off menu at any time, for example, on the Galaxy S21 Lock screen, Home screen, or when using any apps.

How to power on Galaxy S21?

When the phone is off, you can power on Galaxy S21 by holding the Side key for a few seconds.

It is not necessary to wait for the bootup screen to release your finger from the Side key. 2-5 seconds are sufficient.

You cannot power on Galaxy S21 if the battery level is too low (less than 1%). In this case, you should charge the Galaxy S21 battery.

If Galaxy S21 was powered off automatically due to low battery, it would NOT power on automatically when you connect it to a charger. This is different from some old Galaxy phones.

How to power off Galaxy S21

As mentioned earlier, normally, you may power off Galaxy S21 only if you are required to do so, or you will not use the phone for more than a few days.

During the flight, you may use the phone in the flight mode when the plane is cruising.  But some airlines may ask you to turn off (power off) Galaxy S21. So, do not assume you can use the phone on the aeroplane. Check with the attendant.

You cannot power off Galaxy S21 by holding the Side key.  It will reboot Galaxy S21.

To power off Galaxy S21, you need to use the Power-off menu, as discussed earlier.

On the Galaxy S21 Power-off menu, tap the Power off button to power off Galaxy S21 immediately.

Do not hold the Power off button.  If you hold the button, you will then have the option to reboot the phone into Galaxy S21 Safe mode.

If the phone hangs and you cannot access the Power-off menu, you may reboot Galaxy S21 and then try to access the Power-off menu after the reboot.

If Galaxy S21 cannot reboot properly and you need to power off Galaxy S21, you can reboot Galaxy S21 into recovery mode and then power off the phone.

You may have to wait for the battery to drain out or visit the local Samsung service centre if you cannot reboot Galaxy S21 into recovery mode either.

How to reboot Galaxy S21?

There are a few ways to reboot Galaxy S21, including:

  1. From the Power-off menu, if you can access it from the quick settings panel or by holding the Side key for about 2-3 seconds.
  2. Hold the Side key for more than 5 seconds to reboot the phone.
  3. Hold the value down key + side key together for more than 7 seconds until the phone reboots (as shown in the screenshot below).

Hold the value down key + side key together for more than 7 seconds to reboot Galaxy S21

Method 1 is usually recommended if you can access the power-off menu.

The first 2 methods reboot Galaxy S21 gracefully. All open files will be close properly before the phone reboots.  So, there will be no data loss.

However, method 3 will lead to a hard reboot (forcing restart). Some files or apps may not be closed properly before the phone restarts. This may lead to possible data loss. Therefore, you may use this method only if the phone hangs and you cannot access the Power-off menu.

Please note, by default, you cannot reboot Galaxy S21 when the screen is locked. The power-off menu will ask you to unlock the phone first.

Do you have any questions on how to power on, power off, and reboot Galaxy S21, S21+, and S21 Ultra?

If you have any questions or encounter any problems to power on, power off, and rebooGalaxy S21, Galaxy S21+, or Galaxy S21 Ultra, please let us know in the comments.

The community will help you.

If you have any questions on using Galaxy S21, you may check our detailed step-by-step Galaxy S21 guides:

  • Galaxy S21 new features guides.
  • Galaxy S21 how-to guides.
  • Galaxy S21 camera guides.
  • Galaxy S21 accessories guides.

You can also post questions or share your thoughts on our Facebook page.

The official Samsung Galaxy S21 user manual (PDF) in your local language can be read and download here.

If you want, you can drop us an email on the contact us page.

Don’t miss any Galaxy S21 Guides!

Subscribe to our FREE Samsung Galaxy S21 Tips and Tricks Newsletter now!

We don’t spam! Read more in our privacy policy

Check your inbox or spam folder to confirm your subscription.

Filed Under: How to guides Tagged With: charge Galaxy S21 battery, Galaxy S21 Home screen, Galaxy S21 lock screen, Galaxy S21 quick settings, Galaxy S21 quick settings panel, lock Galaxy S21 screen, power off, power off menu, power on, reboot Galaxy S21, recovery mode, restart Galaxy S21, safe mode, Side key, unlock Galaxy S21

Reader Interactions

Leave a Reply Cancel reply

Primary Sidebar

  • Facebook
  • RSS
  • YouTube

Subscribe to Our Newsletter

Don’t miss any Galaxy S21 Guides!

Subscribe to our FREE Samsung Galaxy S21 Tips and Tricks Newsletter now!

We don’t spam! Read more in our privacy policy

Check your inbox or spam folder to confirm your subscription.

RSS Headphone & Earbuds Guides

  • AirPods Pro 2 New features explained
  • What is Samsung Seamless Codec? 4 things you should know about this new codec
  • How to use widgets to check battery levels and control Galaxy Buds 2, Galaxy Buds Pro, Galaxy Buds Live, Galaxy Buds+, and Galaxy Buds?
  • AirPods 3 vs AirPods Pro: which one should you choose?
  • AirPods 3 vs AirPods 2: Top 8 improvements and new features of AirPods 3
  • How to Use and Adjust Force Sensor on AirPods Pro like a Pro?
  • Galaxy Buds 2 vs Galaxy Buds Pro: the Top 8 Pros and Cons
  • 4 ways to check Galaxy Buds Live battery level

RSS Galaxy S22 Guides

  • How to use Maintenance Mode on Galaxy S23, S22, S21, and S20 with Android 13 (One UI 5)?
  • How to extract text from photos and images on Galaxy S22, S21, and S20?
  • A complete list of the new features of One UI 5.1 update for Galaxy S22, S21, and S20
  • How to use multiwindow on Galaxy S22, S21, and S20?
  • How to Use the Help Icon and Histogram for Pro Camera Mode in Android 13 (One UI 5) Update for Galaxy S22, S21, and S20?
  • How to customize the call background on Galaxy S22, S21, and S20 with the Android 13 update (One UI 5)?
  • How to Automatically Add and Customize Watermarks on Photos on Galaxy S22, S21, or S20 with the Android 13 update (One UI 5)?
  • The Definite Guide to Stack Widgets in One UI 5 on Galaxy S22, S21, and S20
  • Top 13 new features in One UI 5 update (Android 13 update) for Galaxy S22, S21, and S20
  • Master Galaxy S22 Lock Screen Settings

RSS Chromecast Guides

  • How to enable developer options in Chromecast with Google TV?
  • How to use Chromecast to stream music to dumb speakers (as Chromecast Audio does)?
  • How to factory data reset Chromecast Audio?
  • How to setup Chromecast Audio?
  • What’s new in the new Chromecast (Chromecast 2015)
  • How to use Chromecast on Amazon Fire tablets (Fire HD, Fire HDX and Kindle Fire HDX)
  • Android screen casting for Chromecast is now supported on all Android devices with KitKat 4.4.2 or later
  • Comparison of 5 methods for streaming local media files to Chromecast
  • Google Cast SDK opens door to public: more apps will work with Chromecast
  • Privacy

Tags

Android 11 Android 12 app icon app shortcut Apps screen camera camera app camera quick launch charge Galaxy S21 battery fingerprint scanner Galaxy S21 Galaxy S21 camera settings Galaxy S21 Home screen Galaxy S21 Home screen edit mode Galaxy S21 layout Galaxy S21 LED Wallet Cover Galaxy S21 lock screen Galaxy S21 quick settings Galaxy S21 quick settings panel Galaxy S21 settings Galaxy S21 Smart LED View Galaxy S21 Ultra Home screen hybrid zoom layout of Galaxy S21 lock screen long tapping navigation bar navigation button navigation gestures NavStar notification notification icon power off power off menu reboot Galaxy S21 screen lock Side key status bar status icon touchscreen gesture User Manual wallpaper widget wireless charging

Copyright © 2023 · Galaxy S21 Guides@GadgetGuideOnline.com · Powered by WordPress with Genesis Framework · Hosted by PTRhosting
Samsung Galaxy S21 how-to guides, user manuals, tips and tricks for Samsung Galaxy S21, Galaxy S21+, Galaxy S21 FE and Galaxy S21 Ultra owners.
Disclaimer: Samsung, Galaxy, Galaxy S21, Galaxy S21+ (S21 Plus), Galaxy S21 FE and Galaxy S21 Ultra are trademarks of Samsung. Android is a trademark of Google. This website is NOT affiliated with Samsung or Google in any way. All the information provided on this website is provided on an "as is" and "as available" basis and you agree that you use such information entirely at your own risk.
Galaxy S21 Guides@GadgetGuideOnline is a member site of GadgetGuideOnline.com : Guides for your Gadgets.

Add Samsung Galaxy S21 Guides to your Homescreen!

Add
pixel