Upgrade paths for Android device
There are few methods of getting the latest firmware onto your device, most of them require one ingredient: correctly signed OTA (usually: update.zip) file or… patience. Once obtained we can start a manual update process. Usually, various ODMs provide more than one way of achieving this goal.
1. Use default client
Usually, each device has its own update client. From time to time this application will perform a check in a background with the server, in order to verify if there is a new update or not. The main issue with this solution is… user’s patience. As many manufacturers are likely to stage roll out new updates (only certain number of user will receive new software at a particular time) you might face even few week’s delay.
Advantages: get original firmware update + seamless customer experience
Drawbacks: might take a while to get update (while others already have it)
2. Recovery mode
If you don’t want to wait for update arriving via the official channel, you can search for the update file yourself (just ensure the file is dedicated to a particular model of the phone you have). Once you get it into your hands you can start the manual process. Recovery itself gives you 3 options (most common ones).
This option enables special ADB protocol allowing to send update file directly from your PC. Once option (‘apply update from ADB‘) is selected you can transfer the file from your machine using the following command:
adb sideload <path-to-file>/update.zip
Once the transfer is completed the update process will start.
Advantages: Update directly from your computer
Drawbacks: File transfer from PC might take a while + might require additional drivers + require for ADB
b. Update via SD Card
Simply copy the update file onto the SD Card, insert it into device, select option (‘apply update from external storage‘) and then confirm file selection and voila – job done your device is updating. What if your device does not have SD Card slot (or you don’t have SD Card)? See option a.
Advantages: Simple alternative if ‘Sideloading’ setup is troubling
Drawbacks: Device has to support SD Cards
c. Update via cache
As a root, you could push an update to a location on cache partition. Then use recovery to apply this update.
Advantages: It exists (?) as alternative if others fail (not available)
Drawbacks: Require ADB and root access
Check my other post if you face any problems with updating your device: OTA update recovery errors