I have an STM32F7508-DK board and have a makefile based baremetal project. Is there any bare metal USB drivers (for MSC) that I can use (not HAL drivers)?

[Tesla DeLorean]

You might want to check what commercial stacks offer.

O​ther than that you could perhaps compile as a library and then link that to your register level code. Or tolerate a hybrid approach.

[Manoj E]

Thanks, I guess the library option is one way to go. Do you know of any guide that I can follow or any reference examples?

[Piranha]

https://github.com/hathach/tinyusb/tree/master/examples/device/msc_dual_lun