The download folders on this site are

• PSoC Designer V5 Installation Files (contains only the SVG viewer and links to the Infineon site)
• EA4FRB Firmware V13
• G1OJS Firmware

If you just want to load up the latest firmware, download the .hex file from the G1OJS folder plus the .zip file containing the firmware loader (SARK100_Firmware_Loader.zip). To load the new firmware, follow the instructions in the SARK100 User Manual at page 72 & 73 (Appendix F).

If you want to revert to the EA4FRB firmware, simply download the .hex file from the EA4FRB folder and follow the same process.

If you want to play with the source code, download the relevant .zip file and, if you need to, look at how to update the firmware from source code on Windows 10.