Please check whether your local network supplier frequency can cover the frequency of your phone.

Press the power button and volume down button at the same time

Please follow on these steps:
“Setting” -> “About phone” - > “Wireless update” - > “Check for updates” - > Update -> Done

As we all know, you want to compare two things, one aspect of the difference must be compared under the same conditions; Similarly, to compare the signal difference between the two phones, two mobile phones must be under the same conditions.
Phone signal comparison premise
1) The same type of SIM card
2) The same network standard: for example, are in the 4G network, are under 2G network.
3) The same location: This includes base station location and the location of your phone, this condition requires special methods can view.
When the above three conditions are satisfied, Go to Settings - About phone --SIM card status, view the signal strength values, numerical comparison between two mobile phones, the absolute value of the difference within 10dBm is normal. Of course, different models, different brands, there will be differences in signal strength, if that cell phone signal is not normal, you can contact the reseller to apply for warranty.

One year.

You need to ask the seller for return or a replacement.

Dear customer,
You can search accessories on these websites:
http://pt.aliexpress.com/store/2028011
http://www.ebay.com;
http://www.sunsky-online.com/;
http://umispain.es/;
http://www.banggood.com/search/umi.html;
http://www.coolicool.com/cell-phones-c139.html?filter_attr=0.0.0.0.0.0.4339.0.0.0.0

Dear customer,
Please watch guideline video:
https://www.youtube.com/watch?v=e1sdjtxdG5Y

Dear customer,
Press the “power” button and “Vol-” button at the same time and hold on for 3 seconds.
There you go!

During the call found a low voice, how to fix it:
1) During a call, use the “vol+” button to adjust the volume;
2) View foil, leather, etc. Are there blocked the handset? If there are, you should remove them;
3) Replace the time, location, contact, to check whether it’s the network problems.
If the above methods have failed to solve your problem, contact the reseller to apply for warranty or refund.

1) Check which network standard and which frequency band your phone supports
2) Search your local network operator via Google browser to learn more about the latest local network standard and the frequency bands;
3) If there is a frequency bands which your phone supports matched with the local frequency bands, you can use the phone in your country;

Data network switch is turned on or not, if connected to the network but it still prompt the network is unconnected, you need to check by the following methods:
1) Contact your operator to confirm whether your SIM card opened the Internet access;
2)Check whether the current network signal is stable: if the network signal instability, that is easily to lead to network failure, you can try to replace the using environment to make comparison;
3) Turn Airplane mode on, then turn on data networks and try to access the Internet;
4) Reset the Internet Parameters: settings - more - Cellular networks - APN-- reset to the default settings, then try to restart the phone after the reset;
5) Replace the SIM card: Check whether there is a poor contact between the SIM card and the SIM card tray, if change different SIM card, it is still there, we recommend that you contact the reseller to apply for warranty or refund.

After the phone installed the SD card, you can read your SD card in two ways:
1) Enter the settings - storage and USB - SD card (if you can’t read it, the SD card option won’t display);
2) Go to File Manager - Storage - to see if there is an SD card option;
If your phone does not recognize the memory card appears, the following method is recommended by the investigation:
1) Check the capacity of the memory card, to see whether your card is within maximum space limit which your phone can support, and then try to restart the phone;
2) Insert the SD card into another phone, see if you can normally use, or install a different SD card on your the phone (check whether SD card, SD card slot is damaged);
3) Data backup SD card, formatted the SD card to see if it’s normal;
4) Backup important data (contacts, multimedia files, etc.) to restore the factory settings (Settings - Backup&reset - Factory data reset).
If the problem persists, we recommend that you contact the reseller to apply for warranty or refund.

Settings---Backup & reset---Turn on “Back up my data”---Factory data reset

Make sure there is a android phone assistant or driver, then use USB cable to connect the phone with the computer Settings---System (or Developer options)---Tick “USB debugging”

Press the power button and volume down button at the same time

Settings---About phone---Wireless update

Settings---Wi-Fi---Tick “On”

Settings---Apps---All---Messaging---Tick “Launch”

You can try to reset the phone to factory settings, if it doesn’t make any difference, please contact the online customer service representative for help.

Please check whether your local network supplier frequency can cover the frequency of your phone.

1) password, signal strength: Make sure you enter the correct password and check the strength of the wireless signal, if the signal strength is too weak, you can’t connect it successfully;
2)Too many people connect this WiFi: If your phone still show, "Acquiring IP Address" "Saved Connection", "disconnected" , we suggest you to disconnect other equipment, then connect it again;
4) Wireless mac address filtering: enter the wireless router management interface, turn off the filter settings permit or allow your own phone to connect;
5) Try to re-setting the router;
If the problem still exists after you check your phone with all above methods, you should contact your reseller to apply for warranty or refund

Please charge the phone with different USB cable and charger or you can replace a new battery.

You can download a third party software such as the app “Move To SD Card”

Dear customer,
Each UMI purchased from an authorized reseller has a 24 month warranty from the date of purchase, provide by the web-store where you purchased the device.
For any after-sale support, please contact web-store for warranty.
Find more detail information at here:
http://www.umidigi.com/page-newguide.html