Originally Posted by drich290195
I understand that if i put a custom rom on even another stock firmware for another region other than what my phone came with i won't get OTA updates.
That i understand. I was wondering though how does it know that its not the firmware that came with the phone.
For example if i put BTU on my carrier branded S5 it won't update but how does it know thats not what it came with. What is not changing when it gets flashed.
Is it based on IMEI or is there another parameter that does not get changed when flashing another firmware.
Thanks for your help guys i like to really understand whats going on.
I don't know how it works exactly, but here is one of possible ways:
Samsung stores the device's S/N and the initial CSC in its database.
(You can check that by using Kies 3 software > Tools > Firmware Upgrade and Initialization, enter your S/N and Kies 3 will show your initial CSC).
That way, when you perform an OTA update, Samsung will know if your current CSC is the same as your initial CSC or not.