Thanks for the suggestion, however I think I've managed to figure out what the problem is and its my own fault for not checking the basics in the first place! The test rig had a short on D- (loose wire) on the USB, as soon as I tested the boards on their own they worked just fine. Just unfortunate t...

So I'm developing a usb device using an esp32-s3, and after getting a prototype working I decided to copy the bootloader hooks which changed registers into the project from this example which disable the pullup on D+ at boot time to prevent the wrong descriptor getting retrieved (Example code from h...