Can a design be changed from an XU part to and XUF part by simply omitting the quad spi flash part? Are there any other changes required? I am unable to find stock of the XU parts anywhere and have found that Digikey has the XUF version of the part.

I can confirm that the above link is the fix for the VBUS issue. The link to the updated library is broken but can be found here:
https://www.xcore.com/viewtopic.php?t=7184

You just replace the modules with the new ones and do a clean build.

For those wondering, xmos pointed me to the solution here:
https://www.xmos.com/developer/download ... 1.0%29.pdf

I will follow-up on this thread once I test and confirm that it works.

I just assumed not connect it since all of the documentation for the part says not to connect it if you are bus powered... I can add the connection (which I did for testing), but would be nice if this worked as the documentation says that it should.

Board is bus powered. Here is the output: Program received signal SIGBUS, Bus error. [Switching to tile[0] core[1] (dual issue)] XUD_SetReady_OutPtr (ep=<value optimized out>, addr=<value optimized out>) at C:/Firmware/XMOS/sc_usb_audio/module_usb_audio/usb_buffer/decouple.xc:681 681 inuchar(c_buf_c...

I tried setting it directly (#define XUD_PWR_CFG XUD_PWR_BUS), but the end result did not change. No enumeration without vbus connected.

In devicedefines.h, this is present:

#ifndef XUD_PWR_CFG
#ifdef SELF_POWERED
#define XUD_PWR_CFG XUD_PWR_SELF
#else
#define XUD_PWR_CFG XUD_PWR_BUS
#endif
#endif

In xTimeComposer, it shows that the value is defined as XUD_PWR_BUS

I will double-check to be sure.

I am having the same issue as TriHex above. The XU208 will not enumerate when VBUS is disconnected, even when SELF_POWERED is set to 0. I am using the latest version of the stack combined with the zip from the original post. Any idea what this could be?

Yes, it's the same bin file you can create from the instructions in the first post.

There are instructions in the first post for how to create the bin. You will need a way to hold the xmos in reset while you program as well.