Help S8+ Wont Update

[AxelzX]

I recently bought a used S8 plus here in japan and im having problems updating it. The Download updates manually does nothing and every time i tried to Flash the firmware but every time it gives me security check fail bootloader.
System info:
System Info:
Android 7.0
Samsung Experience Version 8.1
Baseband Version G955FDXXU1AQH3
CSC XXV/XXV/SKC

Phone INFO Samsung:
Bootloader Version G955NKSU3CRI3
PDA Version G855FDXXU1AQH3
CSC version G955FOXM1AQH3
Baseband Version G955NKOU3CRI1
Original CSC code XXV
Active CSC code XXV
Avaiable CSC codes INS, ITV, THL, TUR, XEO, XFE, XME, XSG, XSP, XTC, XXV
on the back of my phone it says SM-G955N, download mode is in korean and on the Recovery menu it says G950NKSU1AQG7.

 

[mikedt]

Deleted

 

[mikedt]

Can't find anything for the SM-G955N variant. But I assume it's for Japan, like "N" for Nippon?
Korean variants are SM-G955K.


What are you using to try and manually update, Kies or Smart Switch. What does the Knox Status show, is it "Official" or "Custom"? And Warranty Void counter should be "0x0". If those are not as they should be, then OTA updates won't go through.

 

[AxelzX]

Deleted

It says custom.

 

[AxelzX]

Deleted

Can't find anything for the SM-G955N variant. But I assume it's for Japan, like "N" for Nippon?
Korean variants are SM-G955K.


What are you using to try and manually update, Kies or Smart Switch. What does the Knox Status show, is it "Official" or "Custom"? And Warranty Void counter should be "0x0". If those are not as they should be, then OTA updates won't go through.

I tried using OTA and Smart Switch, Knox Status says Custom and Void is 0x1.
About this phone, on the back of my phone it says SM-G955N, the same as The K version. the problem is that the firmware is from the G955FD. I dont know wish version this phone actually is because of this.

 

[mikedt]

I tried using OTA and Smart Switch, Knox Status says Custom and Void is 0x1.

Yeh, that's definitely been rooted and modified then. Samsung's normal methods of updating will not work on modified devices. That's why you're seeing the security check fail.

Go here, and search for your particular phone varian. Hopefully it has the appropriate updated firmware, and instructions for flashing it. https://www.sammobile.com/firmwares/

 

[AxelzX]

Yeh, that's definitely been rooted and modified then. Samsung's normal methods of updating will not work on modified devices.

Go here, and search for your particular phone varian. Hopefully it has the appropriate updated firmware, and instructions for flashing it. https://www.sammobile.com/firmwares/

I tried Flashing using the SM-G955FD firmwares but they all failed. i get the error secure check fail bootloader every time. i gonna try using the SM-G955N firmware to see if it works.

 

[mikedt]

I tried Flashing using the SM-G955FD firmwares but they all failed. i get the error secure check fail bootloader every time. i gonna try using the SM-G955N firmware to see if it works.

SM-G955FD that's the international dual-SIM variant. And that definitely won't work. Because international S8+ is Exynos processor, and the Japan variant is Qualcomm Snapdragon processor. You must have the correct firmware. The only other S8+ that's Snapdragon, are the China and US variants.

The only other firmware that just might have a chance of compatibility, is the SM-G955U, which is unlocked North American for Snapdragon S8+. But no idea if it would actually work it not.

Custom ROM maybe an option, if available for that variant.