For removable battery, please take away the battery cover and you will see a blue isolator on the battery. Take it away and power on the phone later.

One year.

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

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”.

Settings---About phone---Wireless update.

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

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

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.

“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.