Change CSC then factory reset will it prevent singtel apps appearing forever? What CSC and how to change?
Changing CSC will factory reset the device with everything wiped. That has to happen.
CSC is Consumer Software Customization and denotes to a specific geographical region or carrier branding. While most features of a specific Galaxy device are common globally, there are a bunch of other features that may or not be available to the end users in a particular country and region.
Usually and commonly personalize your device by adding features like your native language pack, screen rotation control, infinite scrolling on home screen, turn on/off camera shutter sound and so on. Tons of features here and there even VOLTE settings
NOT FOR THE FAINT HEARTED! YOU WILL LOSE EVERYTHING IF YOU GO BY DOING THIS!
Usually, you've to type in your phone dialer *#272*Device IMEI# (Insert your Device IMEI). There you will be presented with a menu with all the CSC on your phone. XSP is Singapore, SIN is Singtel, MM1 is M1 and STH is Starhub.
The rest are other regional countries around us but you must avoid those, going to those there is no known way to come back to any Singapore CSC and the dialer code is disabled. The only way to fix is a visit to Samsung Service center