I understand that you are using the FX2LP device. The bulkloop firmware can be found in the below path after the installation of CY3684 DVK.
Unfortunately, I don't have the directory path.
I am working with a Cy8ckit-059 5LP Prototyping kit which has a cy8c588LTI-LP097 in it.
You can check the Project1 of AN56377 depicting the loopback at interrupt, bulk, and isochronous endpoints with Control Center available with Cypress Suite USB 3.4.7 or EZ-USB FX3 SDK
Check this forum link, it may be useful: