
Samsung GALAXY S
The latest firmware for Samsung GALAXY S (SC-02B) is SC02BOMLL1 with Android 2.3.6 (Gingerbread), released on December 17, 2012 for 1 region (CSC). Every official firmware build for SC-02B, 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/SC02BOMLL1

SC-02D

SC-01E

SC-01D

SC-01C

SC-03D
You can find the firmware on the model: SC-02B page.
Yes, all firmware files for SC-02B are 100% official, original, and obtained directly from Samsung servers.
To flash SC-02B, 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 SC-02B.