Unlocked BIOS image for an X360 device, packed as an 8.86 MB RAR; the name does not say which manufacturer or exact X360 model it belongs to, so identification rests on your own board. Unlocked dumps usually have a password or similar lock removed and are programmed onto the SPI flash with an external tool. Read and archive the original contents first, check that the motherboard number printed on the PCB fits the intended model, and confirm the image size equals the capacity of the flash chip before writing.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @biosfilebins. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →