In case of severe problems with Xperia and Sailfish X it may turn out best to reinstall Sailfish OS to the device. This article explains how to do it.
Depending on the problems observed on Xperia X, it may be enough to reinstall ("reflash") Sailfish OS to it. However, if your Xperia cannot use the services of cellular network properly (or at all), then it may be necessary to revert the device back to Android first -- see this article.
NOTE: Reinstalling Sailfish OS means that all data in the device memory will be deleted. Only the SD and SIM cards remain untouched.
Installing Sailfish OS again to Xperia X
Installing Sailfish can be made with Windows, Linux or Mac computers. In the next chapters we have pointers to our official Sailfish X instructions.
Make sure you have the latest available Sailfish OS version downloaded to your computer. If not you can download it from this repository. Please sign in to this service by using the same Jolla account that you used for buying the Sailfish X license.
Check that the contents of your Sailfish OS directory is similar to that in the picture below (which has Sailfish OS version 188.8.131.52 as for example).
Picture: Correct contents of Sailfish X install directory - an example.
In particular, check that you have file "SW_binaries_for_Xperia_AOSP*.img" there (if missing, visit chapter 5: Windows, Linux, Mac ).
Flash Sailfish OS to your Xperia, as instructed in chapter 6: Windows, Linux, Mac.
While connecting the USB cable press the Volume UP button. Then you must see the BLUE light lit (if green, disconnect, reconnect and try again).
After you have completed flashing, the printout similar to that shown in the attached PDF file should appear on your computer screen (Sailfish OS version ID will be different as time goes on).