Hi Vito. I have bootable USB sticks with TCL15 x86_64 that work just fine, and they go back in forth between computers with legacy bios and computers with UEFI.
My guess is that your problem stems from automated tools (e.g., Ventoy, Rufus, Balena, etc.) making assumptions about TCL, your computer (e.g., BIOS vs. UEFI), or your bootloader that are not true. But there are too many variables here to be sure what the problem is. I think ditching the automated tools and creating the bootable USB stick manually, one step at a time, is the best way.
The steps I followed to success are in this thread (first post by Juanito has everything you need for UEFI. For legacy BIOS, I discovered that the USB stick also needs a BIOS boot partition--see reply #51):
https://forum.tinycorelinux.net/index.php/topic,19364.0.htmlNote that I created my bootable USB sticks in 2024, so these instructions are still valid today despite Juanito having written this in 2015!