Copy the extracted files directly to the root directory of your USB drive (don't put them in a subfolder).
This is the most common use for files like this (e.g., updating a Toyota, Honda, or aftermarket Android head unit). sc24606-RTAUpd112.rar
While official changelogs can be vague, users who have already upgraded to this "RTA" (Real-Time Update) version report: Copy the extracted files directly to the root
Blog Post Title: How to Install the [Device Name] Update (Version sc24606-RTAUpd112) updating a Toyota