Dumber Mini Quick Guide

Getting Started

Overview

Front

Front Camera
Speaker / Receiver
P/L Sensor
Display
T9 Keyboard
Main Microphone

Back

Sub Microphone
Rear Camera
Flash/torch
Volume +
Volume -
NFC Antenna
USB Port

Installing the SIM card

Insert the SIM card provided by your mobile service provider.

You can insert two SIM cards to use two phone numbers on a single device. In some areas, data transfer speeds may be slower when two SIM cards are inserted than when only one SIM card is inserted.

Ensure that the ejection pin is perpendicular to the hole. Otherwise, the device may be damaged.
Pull out the tray gently from the tray slot.
Place the SIM card on the tray with the gold-coloured contacts facing upwards. Place the secondary SIM card underneath the tray with the gold-coloured contacts facing downwards.
Gently press the SIM cards into the tray to secure them.
If a SIM card is not fixed firmly into the tray, it may fall out of the tray or not function correctly.
Insert the tray back into the tray slot.
If you insert the tray into your device while the tray is wet, your device may be damaged. Always make sure the tray is dry.
Fully insert the tray into the tray slot to prevent liquid from entering your device.

Removing the SIM card

Insert the ejection pin into the hole on the tray to loosen the tray.

Pull out the tray gently from the tray slot.

Remove the SIM card.

Insert the tray back into the tray slot.

Charging the battery

Charge the battery before using the device for the first time or when it has been unused for extended periods.

Connecting the charger improperly may cause serious damage to the device. Any damage caused by misuse is not covered by the warranty.

To save energy, unplug the charger when it is not in use. The charger does not have a power switch, so you must unplug it from the electric socket to avoid wasting power. The charger should remain close to the electric socket and easily accessible while charging.

Connect the USB cable to the USB power adaptor.

Plug the USB cable into the device’s multipurpose jack. See the diagram.

Plug the USB power adaptor into an electric socket.

After fully charging, disconnect the charger from the device. Then, unplug the charger from the electric socket.

Device overheating situations and solutions

When the device heats up while charging the battery

While charging, the device and the charger may become hot. This does not affect the device’s lifespan or performance and is within the device’s normal operating range. If the battery becomes too hot, the charger may stop charging.

Do the following when the device heats up:

Disconnect the charger from the device and close any running apps. Wait for the device to cool down and then begin charging the device again.

If the lower part of the device overheats, it could be because the connected USB cable is damaged. Replace the damaged USB cable with a new one.

When the device heats up during use

When you use features or apps that require more power, or use them for extended periods, your device may temporarily heat up due to increased battery consumption. Close any running apps and do not use the device for a while.

The following are examples of situations in which the device may overheat. Depending on the functions and apps you use, these examples may not apply to your model.

During the initial setup after purchase or when restoring data
When downloading large files
When using apps that require more power or using them for extended periods
When playing high-quality games for extended periods
When recording videos for extended periods
When streaming videos while using the maximum brightness setting
When connecting to a TV
While multitasking or running many apps in the background
When using Multi Window
When updating or installing apps while recording videos
When downloading large files during a video call
When recording videos while using a navigation app
When using large amounts of data to sync with the cloud, email, or other accounts
When using a navigation app in a car while the device is placed in direct sunlight
When using the mobile hotspot and tethering feature
When using the device in areas with weak signals or no reception
When charging the battery with a damaged USB cable
When the device’s multipurpose jack is damaged or exposed to foreign materials, such as liquid, dust, metal powder, and pencil lead
When you are roaming

Do the following when the device heats up:

Keep the device updated with the latest software.
Conflicts between running apps may cause the device to heat up. Restart the device.
Deactivate the Wi-Fi, GPS, and Bluetooth features when not using them.
Close apps that increase battery consumption or that run in the background when not in use.
Delete unnecessary files or unused apps.
Decrease the screen brightness.
If the device overheats or feels hot for a prolonged period, do not use it for a while. If the device continues to overheat, contact our Service Centre.

Keyboard functions

D-pad: Scroll through options in a given direction. While the screen is off, switch audio tracks.
D-pad center: Select the highlighted option or confirm input. While the screen is off, pause or play audio tracks.
Menu: Press once to browse notifications. Press again to open the Quick Settings panel. Long-press to view recent apps.
Back: Delete characters when entering text. Go to the previous screen in an app.
Call: Answer an incoming call. Call the number entered in the dialer.
Power / End call: Hang up or reject an incoming call. Go to the home screen while in an app. Lock the phone while on the home screen. Turn the screen on if it is currently off.
Alpha-numeric: Dial a number while on the home screen. Enter numbers or text if the TT9 app is active. Enter your PIN if the phone is locked, even with the screen off.
Zero / Space: When editing text, press once to add space or long-press to enter “0”.
One / Symbols: When editing text, press once to enter symbols or emoticons, long-press for “1”.
Asterisk: When editing text, press once to switch word capitalization. Long-press for special commands.
Hash key: When editing text, press to switch between predictive, ABC, and number modes. Long-press to change the input language. Outside text editing, hold to switch between normal, silent, and vibrate modes.

Notifications and quick settings

Pressing the menu key ( , top right) opens the notification panel. Here you can browse notifications using D-pad up and down, dismiss them using D-pad left, and open them using D-pad center.

Pressing the menu key again opens Quick Settings, where you can change the volume, toggle airplane mode, or change the audio profile. Use the D-pad up, down, left, and right keys to navigate and change settings.

Zooming out the screen

Some applications may not render correctly on the small screen of the Dumber Mini. Typical scenarios involve important UI elements being drawn off the screen or overlapping each other, preventing interaction.

For such cases, use the Zoom out screen option. This is available in the “Recent Apps” menu. To access it, press and hold the menu ( ) button and select “Zoom out screen”. When you no longer need the “Zoom out” feature, select the same button to turn it off.

Notification light

Important notifications, such as missed calls or new text messages, will turn on the keyboard backlight, even while the screen is off. This feature can be turned off in Settings->Notifications->Notification Light.

The same menu can be used to allowlist other apps so their notifications also turn on the backlight. The keyboard backlight is always on by default while the screen is on. This can be disabled in Settings->System->Keyboard.

Typing with T9

DumberOS includes the open-source TT9 app for typing text. Until TT9 is configured, the system will use the default Android on-screen keyboard.

To configure TT9, either follow the instructions in the setup wizard or tap the TT9 icon in the app drawer.

In the app’s “Initial Setup”, make sure the keyboard is enabled, TT9 is selected as the default keyboard, and the system spell checker is disabled.

Go back to the top-level TT9 menu and select Languages. Make sure your chosen languages are enabled, then select Load Selected to download the appropriate dictionary files.

TT9 is now enabled for typing. When a text input field is focused, the app’s interface should appear at the bottom of the screen. You can now use the phone’s keys to type text!

If you want to enter text but the interface is not visible, try tapping the text field or press the # key.

While typing, press the # key to cycle between the ABC, 123, and predictive modes. Long-press the # key to cycle between available languages.

In some situations it’s more convenient to use the on-screen keyboard (for example to enter a password). To switch, hold the * key and press 8, or select the last item in the bottom menu. When using the on-screen keyboard, hold the space bar to switch back to TT9.

For a complete manual, please visit: https://ddmio.eu/tt9

Installing applications

DumberOS includes a small collection of Android apps available to install, such as WhatsApp, Maps, Music Player, Uber, etc. These apps are tested and confirmed to work well on the device. To access them, open “More Apps” on your main screen.

For a wider range of applications, you can install Aurora Store, also available under “More Apps”. Please note that not all applications available there are compatible with DumberOS.

Blocking unwanted apps

We recognize that some customers want to limit the set of apps available on the device, for example in order to avoid social media or to make the phone more child-safe.

To block apps, go to Settings->App Blocker. You can optionally set a PIN that will lock this setting in the future (this is separate from the device lock PIN). In App Blocker, you can temporarily or permanently block an app or disable app installation. Permanently blocked apps or the access PIN can only be reversed by factory resetting the phone.

Contactless payments

Dumber Mini features an NFC sensor that supports contactless payments. It’s important to note that Google Pay is not compatible with DumberOS, so you will need to use a different application.

We recommend Curve Pay for customers based in the European Union, as well as in the United Kingdom, Norway, Iceland, Liechtenstein, and Switzerland.

It’s also worth checking whether your local bank’s app supports direct NFC payments (not through Google Wallet).

Troubleshooting

Mobile data not working

Check that the SIM card is seated correctly in the SIM tray and that you have a mobile signal.
Make sure mobile data is enabled in Settings->Network&Internet->SIMs->Your Carrier->Mobile data. If you are roaming, make sure “Roaming” is also enabled on that page.
Check that your APN details are entered correctly in Settings->Network&Internet->Your Carrier->Access Point Names. Consult your carrier’s documentation for the correct APN setup.
Try using a SIM card from a different carrier if possible, to test whether this is an incompatibility with your carrier.

Calling or texting not working

Make sure the SIM card is seated correctly in the SIM tray and that you have a mobile signal.
Check whether Settings->Network&Internet->SIMs->Your Carrier->VoLTE or 4G calling is enabled.
If calling works but you are not receiving text messages, make sure you have turned off RCS and/or iMessage on your previous phone. Consult Apple or Google help pages for details.
Try using a SIM card from a different carrier if possible, to test whether this is an incompatibility with your carrier.

WhatsApp displays the error “You need the official WhatsApp to log in”

Despite the error message, this is not related to your WhatsApp installation. It occurs because the Dumber Mini is not a Google-certified device. To work around this issue, please add your Dumber Mini as a linked device in WhatsApp. Consult WhatsApp documentation for details.

App not working because of a “rooted device” or “uncertified device” error

Your DumberOS device is not rooted and is fully secure. However, it is not certified by Google, which some apps assume as a security requirement. We are constantly looking for ways to make the most popular apps compatible, but for some apps this is simply not possible. Please write to us about the app you are trying to use, and consider getting in touch with the app’s developer to raise the issue as well.

Battery draining too fast

The expected battery life of the Dumber Mini is approximately 1.5 to 2 days with moderate usage. If your phone doesn’t last through the day, we can assume that something is draining the battery abnormally.

Please go to Settings->Battery->Battery Usage and check whether any of the installed apps are using more battery than expected. Note that the app “Trebuchet” is the system launcher and is often incorrectly reported as draining the battery.
Put your phone in airplane mode for a few hours, and check if the battery drain stops. If so, it might be caused by a weak signal or an incompatibility with your carrier.
As a last resort, factory reset your phone, turn it on without any further interaction, and re-check the battery drain.

Phone turns the screen on, reboots, or dials emergency services while in a pocket

The power/end call button on the Dumber Mini is positioned in a way that makes accidental presses fairly easy. Pressing it opens the lock screen, where you can change some settings or, after holding it for a few more seconds, call emergency services. Holding the power button for ten seconds or more causes the phone to reboot in any situation.

If your phone uses a PIN screen lock, it’s possible to start entering the PIN even when the screen is off. To turn this feature off, go to Settings->Security->Device Unlock->Screen lock settings (the gear icon on the right), and toggle “Wake screen with PIN keys”.

We recommend using a protective case and avoiding tight pockets to prevent accidental key presses.