
Samsung Galaxy Folder
Every official firmware build for SM-G150NK, newest first: one row per build with all regions (CSC) that received it.

SM-G935TZK

SM-G930AZK

SM-G935AZS

SM-G935TZS

SM-G935AZK

SM-G935TZD

SM-G975WC

SM-G975FC
You can find the firmware on the model: SM-G150NK page.
Yes, all firmware files for SM-G150NK are 100% official, original, and obtained directly from Samsung servers.
To flash SM-G150NK, you need to download the appropriate firmware, put your device into Download Mode, and use the Odin tool to load the BL, AP, CP, and CSC files.
Downgrading is only possible if the bootloader version (binary bit) of the old firmware matches the current one. Always check the binary version before flashing SM-G150NK.