Thank you very much for the input. Unfortunately, I can't find anything there that I can include in my current project or that seems compatible with the setup I have partially working. The code file is attached. I'll summarize what I'm doing to see if anyone can give me a tip on how I could continue...

I am developing a system based on an ESP32 S3 where I have two flash memories connected to an SPI port (SPI3) with different CS (chip select). The final goal is to make these memories mountable (as an MSC) on a PC when connecting the ESP32 via USB. I can successfully mount them on the system (ESP32)...