Installation & setup

  • Download from Google Play Store.

  • When you open the App for the first time, you will be welcomed with a step-by-step tutorial screen to enable some mandatory and few optional permissions that CoverScreen OS requires to simulate a secondary OS like experience on your phone's cover screen:

    1. Appear on Top permission (mandatory)

    2. Accessibility Service (mandatory)

    3. Notification Access (mandatory)

    4. Microphone (optional - however, this will disable Voice Keyboard)

    5. Nearby devices (optional - for Bluetooth Quick Toggle)

  • Once all permissions are granted, you may fold your phone and be welcomed with CSOS's (CoverScreen OS) boot screen.

Home Navigation System

Home Navigation System

Your new Navigation System to access best of both CoverScreen OS and Samsung's stock OS on your cover screen:

  • Stock OS - around 15% of the cover screen at right edge acts like a gesture area:

    1. Swipe down from extreme right side of your screen - Opens the Quick Toggles on Z Flip 4 and Sound/Brightness controller on Z Flip 3.

    2. Swipe up from extreme right side of your screen - If you have Samsung Pay enabled, it gets launched.

    3. Swipe left from extreme right edge of your screen - Access to the very limited Samsung widgets.

  • CoverScreen OS - around 85% of the cover screen acts as a gesture area:

    1. Swipe down - Opens CSOS's native Quick Toggles screen which can be customized to add virtually any type of Toggle you wish to have.

    2. Swipe up - Opens CSOS's Media Screen, which lets you quickly launch your favorite music App if it's already not active and otherwise shows all your active music sessions.

    3. Swipe left - Opens CSOS's Widget Screen, where you can add any Android App's widget you like, pixel perfect aligned to your cover screen.

    4. Swipe right - Opens CSOS's enhanced Notifications Screen, you can not only read full notifications but take actions, open them directly on cover screen or even reply to them with Voice/T9/QWERTY full keyboard.

    5. Single tap - Opens the App Drawer that you can use to launch any App directly on cover screen.

App (Drawer) Navigation System

Once you launch any App with CSOS's App Drawer, to navigate around you have two gestures available:

  • Swipe left from extreme right edge of cover screen - simulates a system 'back' action on the App, just like on your main screen.

  • Swipe up from extreme bottom edge of cover screen - takes you back to the App Drawer of CSOS.

  • Exiting the App Drawer:

    1. You can swipe right from anywhere on the screen while the App Drawer is displayed to exit to home screen.

    2. Turning the cover screen display off and then on, takes you back to home screen.

Customisable CSOS App Drawer

App Drawer customization

  • Set App Icons to either show label (App name) or make it hidden.

  • Switch between either Grid or List style icons.

  • In case of Grid style, you can switch between 4/5/6 columns.

App Drawer menu bar

  • Orientation toggle

    1. Auto - Reads orientation of the App as set in the main settings of CSOS on main screen (landscape/portrait,) if no preference is set, it allows the App to choose an appropriate orientation. Note: Actual auto rotation based on sensor isn’t enabled as that will draw heavy battery power.

    2. Landscape lock - Irrespective of preference set in the main settings of CSOS, temporarily locks all App launches to landscape mode.

    3. Portrait lock - Irrespective of preference set in the main settings of CSOS, temporarily locks all App launches to portrait mode

  • Search - Opens a screen of alphabets, clicking any of the alphabet, sorts the App drawer by that letter.

  • A/Z, Z/A - pressing it toggles sorting app drawer either A-Z or Z-A.

  • Recents - sorts app drawer by the last launched App on CSOS.

  • Favorites - shows only favorite apps (as set in main settings of CSOS on main screen.)

Widget size / zoom level

Although every widget you add to CSOS is pixel perfect aligned to the size of your cover screen, the actual content of the widget may work best for you with a different size / zoom level, totally depends on the content of widget. CSOS allows you to choose between two sizes/zoom levels for each widget, you can toggle between them by opening CSOS on main screen > Widgets tab at bottom > beside every widget's switch there is a Icon with four arrows > click to toggle between zoom in (large) / zoom out (small).

The default size/zoom level is large/zoomed in for all widgets. An example effect of the size/zoom difference is as shown below with the Gmail Widget:

Default widget size - zoomed in/large

Widget size/zoom level toggled in CSOS App on main screen

CSOS Native Quick Toggles

Quick Toggles

CSOS comes in-built with a bunch of native Quick Toggles

  • Bluetooth toggle

  • Flashlight toggle

  • DND toggle

  • Flex Mode - lets you use cover screen while your phone is kept in tent style (half folded) mode (that's how I took photos of CSOS ;) )

  • Caffeinate - toggling it on will keep the cover screen awake until you explictily turn it off by toggling it again or pressing the power button

  • Power Dialog - shows system power dialog to shutdown/restart phone.

Powerful custom Quick Toggles (powered by Bixby Routines) added to CSOS

One of the core features of CSOS is that, you can create your own powerful Quick Toggle to almost do whatever you wish for. Your mileage may vary depending on what Apps (Quick Toggle providers) you have installed on your phone.

In general, if you enable Bixby routines on your phone, that will probably the only Quick Toggle provider you need to build whatever powerful Quick Toggle you want:

  • Enable Bixby Routines on your phone

  • Open CSOS app on main screen > Quick Toggles tab at bottom

  • Click on + button

  • Choose Bixby Routines as your Quick Toggle provider

  • Select your existing Bixby Routine or create a new one

  • Once done, go back and enable the newly created Quick Toggle powered by Bixby routine in CoverScreen OS

Edge Lighting Notification in action!

Multi-colored Edge Lighting Notifications

Enabling Edge Lighting notifications is as simple as turning on the switch in the App on main screen. There are three different color configurations that you can apply:

  • Default - Edge Lighting glows around the edges of your cover screen whenever a new notification pops up with the color you set in the CSOS settings (by default, picks up your theme color.)

  • App color - Edge Lighting glows up with the prominent color of the App's Icon.

  • Multi color - Edge Lighting glows up with the prominent color of all Apps' Icons which have unread notifications.

Voice, T9, QWERTY Keyboard

CSOS Keyboard

CSOS Keyboard with auto-pop up whenever you hit a text field in an App on cover screen or when you want to reply to any notification.

Switch between T9/QWERTY Keyboard:

  • When on T9 Keyboard, long press the bottom right key (beside the 0) to switch to QWERTY

  • On QWERTY long press the keyboard icon to switch to T9

CSOS Caller ID for incoming WhatsApp Business Call

Caller ID screen for VoIP Apps

  • By default you can accept/decline an incoming call or hang up an ongoing call only if it's network/carrier based. CSOS allows you to do the same actions when you have an incoming/ongoing WhatsApp, Telegram and other VoIP based calls.

  • You have to manually enable in the App on main screen, the Apps for which you want to see caller ID. There is an experimental Universal Caller ID option, which will attempt to enable Caller ID for any unknown/incompatible app as well, play around with it.

Flex Mode (tent style/half (folded) usage

Flex Mode (Quick Toggle)

You may have wondered how did I take those pics of CSOS with phone half folded or the above video, well, this is courtesy of CSOS's Flex Mode quick toggle:

  • On cover screen, swipe down to CSOS Quick Toggles.

  • Click on Flex Mode quick toggle.

  • Proceed to unfold your phone.

  • Now you will be in Flex Mode, where you can use your cover screen while the phone is unfolded.

  • Fully folding/closing your phone will exit Flex mode.

CSOS’s music screen

Powerful Music Screen

  • On Music Screen (Swipe up from home of CSOS), when no music is playing, you can click on ‘play music’ button, this will open App Drawer with all the available music App on your phone to quickly launch it and play some music.

  • Multiple music sessions can be active (can be accessed by swiping right/left on music screen) this is similar to the music playback cards notification on main screen.

Smart reply based on context

Smart Replies

  • On Samsung's Stock OS, the Quick Reply options you get are basically canned responses and they are fixed. CSOS generates smart replies based on the conversation context.

  • Upto 3 smart replies are generated.

  • The replies generated could be mix of texts and emojis.

  • For now, only messaging Apps support smart replies.

  • Only English language with non-sensitive conversation is eligible for smart replies.

Tips & tricks

  • When a music session is started, clicking on album art/song name/artist name will allow you to open its main App directly on cover screen.

  • While you're in Flex Mode, you can exit it by double tapping on main screen as well.

  • Enter vs Send button on CSOS Keyboard:

    1. After you're done typing your text, you may either enter it or enter & send altogether.

    2. On different Apps you may have to use different keys to succesfully type in and send your message, play around with it.

  • By default CSOS Quick Toggles are not restricted by specific toggles/features, but the slot. You are free to use whatever Quick Toggle you may put in the first 6 slots, so you can re-arrange them as per your favorite 6 toggles. Same applies for Widgets (but limited to 3.)

  • Certain widgets can be clicked such that, their corresponding action/App will be opened directly on the cover screen.

  • If you want to use CSOS for extended period of time, use the Caffeinate Quick Toggle to keep the screen awake.

Support Dev Pack

  • Allows you to add more than 3 widgets to CSOS (you can add any Android App widget to CSOS, even factory reset phone has easily 30+ widgets available without no extra App installation.)

  • Makes more than 6 slots available for any number of Quick Toggles.

  • Access to full menu bar on the App Drawer.

  • Choose Smart Replies for chat messages.

  • Open Notifications directly on cover screen.

  • Reply to notifications directly from cover screen.

  • Music screen will allow active music/media sessions's App directly on cover screen.

  • Clicking on widget sometimes opens another screen/App, this can be directly opened on cover screen (limited compatibility.)

  • Enable notification count badge on App Icons in the App Drawer.

  • Change App Drawer Icons style - Grid/List.

  • Run Apps either in landscape or portrait mode.

  • Hide unused Apps from App Drawer.

  • Customize Grid of Icons to show 4/5/6 columns.

  • Set Favorite Apps.

  • Set App Drawer to show by default either Recents or Favorite Apps.

  • Unlock multi-colored Edge Lighting option.

  • Resume Apps launched on cover screen onto main screen when you unfold.

  • Extended screen time out options.

  • If you're privacy conscious, you can hide notifications' content on cover screen, until phone is unlocked with your fingerprint.

  • Set default keyboard to be QWERTY instead of T9.

  • Enable Caller ID screen for more than one compatible VoIP app.

  • Enable Universal Caller ID, experimental feature.

  • More features in future.


  • How do I access Samsung Pay when CoverScreen OS is on?

    1. As part of the Navigation System, Samsung Pay is always accessible from home screen by swiping up from extreme right edge of screen.

  • The camera App and other Apps accessing camera doesn't work on cover screen?

    1. Apps launched on cover screen do not actually understand the flip phone configuration, including the Samsung's camera App.

    2. The proper way to access camera and take photos is the Samsung built shortcut - double press power button to launch the special App on cover screen to access camera.

  • CoverScreen OS launches App when in pocket sometimes, explanation?

    1. Apparently, the cover screen is prone to accidental touches when kept in pocket (that is screen facing your skin.) I will be working on a feature which will add some kind of lockscreen for cover screen, only after your action will it allow Apps or anything to function on cover screen.

    2. For now, please be conscious abou keeping your phone in pocket such that the screen isn't facing your skin.

  • How to get rid of 'CoverScreen OS is displaying over other Apps' System notification?

    1. Long press the notification > settings > notification categories > then turn off 'All Notifications' under 'Display over top of other apps' section.

  • What's the difference between different pricing options for 'Support Dev Pack'?

    1. Monthly and yearly subscription grants you access to all features on all of your devices.

    2. Any contribution option under 'Z Flip 3 only!' / 'Z Flip 4 only!' grants you lifetime access to all features on your Z Flip 3 / Z Flip 4 only!

    3. Any contribuiton option under 'Z Flip 3+' / 'Z Flip 4+' grants you lifetime access to all features on all your current devices (Z Flip 3, Z Flip 4) as well as on any future device model that CSOS may support.

  • Future plans, more features?

    1. Oh, there is a lot of pending features in my to-do list that I shall be continously working on and rolling out depending on the support. Right now, am the only one doing coding, taking photos, replying to users and even writing this post, it's quite resource heavy task especially with the niche userbase and a tiny fraction of users who actually support this project.

  • How can I support the development of this project beyond contributing via 'Support Dev Pack'?

    1. Most of the mainstream main YouTubers and reviewers of Z Flip series of phone aren't aware of CoverScreen OS, they point out so many lack of features built by Samsung, which are already implemented by CoverScreen OS, if you can help me get their attention to discover CoverScreen OS, it will heavily help the development and future of this project.