A FEX file defines various aspects of how the SoC works. It configures the GPIO pins and sets up DRAM, Display, etc parameters. It is Allwinners predecessor for the devicetree.
Each line consists of a key = value pair combination under a [sectionheader]. All three, [sectionheader], key and value are case-sensitive. For comments a semi-colon (;) is used and everything following a semi-colon is ignored. The chip does not parse a textual version of a fex file, it gets cleaned and compiled by a fex-compiler. A reverse engineerd open source version exists in the sunxi-tools repository. Also a de-compiler which takes a binary script.bin and creates a textual script.fex. Usually, script.bin can be found on the nanda boot partition on A10 devices.
Sticky-note-pin.png Note: The mainline Linux kernel makes no use of FEX / script.bin, and relies on the device tree model instead (.dtb files).
