If not then please specify which Rom you are referring to. Typically Stock Firmware from Manufacturer can only be flashed via PC in Most of the cases. That is unless a developer has made a flashable version.
I want to update my tablet lenovo a5500 to the latest virson . this is the information you need . my tablet is rooted and i want to know why is the keyboard is very slow in writtting and my sister tablet lenovo a3500 is very fast in writting
If not then that's good place to start. You do are aware, that there settings in Settings > Languages & Input to change the behaviour of your default keyboard right ? Sometimes if the associated dictionary is too big the keyboard may slow down.