How to update firmware without any cost

the way to update the firmware on my phone?
users can improve firmware on the cellphone by both car update or guide replace.
＊if you do now not acquire notices of firmware updates, please refer to Techseaker

a.  Auto update

be aware: during the replace system, please charge your smartphone with AC adaptor or ensure the smartphone has at least 15% battery existence.
tap "test update" in "Settings" -> "about" -> "system replace" to test if the firmware is trendy.
If there is the more modern model to be had, please follow steps proven on display to execute the update.

B. Manually update

If you are going to update your firmware you may need to look at this site and here you can find all the types of firmware update
Techseaker Manully update