It is possible you are referring to one of the following:
: Extremely small file size (~330 KB) and requires no installation. usbutil ver 102
While effective, version 1.02 is an older release. Most users in the retro-gaming community now prefer USBUtil v2.0 v2.2 (English/Spanish) for improved stability and wider game support. using this tool? USBUtil 2.0 Full Version Download | PDF - Scribd It is possible you are referring to one
If you are using USB Advance/Extreme, you cannot simply copy the ISO to the drive. You must use USBUtil to "install" it. usbutil ver 102
USBUtil uses the older USB 1.1 protocol drivers (via USB Advance). This results in and compatibility issues with some games (e.g., Jak and Daxter series often struggles on USB Advance).