Samsung Galaxy Folder (SCH-W899) Firmware Overview
The archive lists 2 official builds for the Samsung Galaxy Folder across 1 region (CSC). The newest one is W899HD18, released April 18, 2014 with Android 2.3.6.
How to Flash SCH-W899 Firmware
Put the Samsung Galaxy Folder into Download Mode, load the BL, AP, CP and CSC files into Odin on a Windows PC and press Start. Pick a build with the same or a higher Bit than the one installed — a lower bootloader binary will be rejected.