
Samsung Galaxy Tab 4 8.0
Every official firmware build for SM-T330X, newest first: one row per build with all regions (CSC) that received it.
Specifications of SM-T330, a regional variant of the same device. Chipset and SIM lines are left out: they can differ by region.

SM-T330NU

SM-T332

SM-T230X

SM-T320X

SM-T321
You can find the firmware on the model: SM-T330X page.
Yes, all firmware files for SM-T330X are 100% official, original, and obtained directly from Samsung servers.
To flash SM-T330X, 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-T330X.