
Samsung Galaxy S5 LTE-A
Every official firmware build for SM-G901F, newest first: one row per build with all regions (CSC) that received it.
Each firmware build has its own page at https://samfirm.shop/build/{PDA}, where {PDA} is the build number from the list above. Example: https://samfirm.shop/build/G901FXXU1CRI2
Box codes of SM-G901F for different colors and markets. Firmware is chosen by the model code SM-G901F and your region (CSC), not by the SKU.

SM-G900AZ

SM-G9098

SM-G903W

SM-G800X

SM-G9198
You can find the firmware on the model: SM-G901F page.
Yes, all firmware files for SM-G901F are 100% official, original, and obtained directly from Samsung servers.
To flash SM-G901F, 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-G901F.