Bmarkus, Lee:
Normally when you buy a usb stick it comes as removeable media. Hardware of the usb stick allows to set this media to be as removeable or look like a hard disk drive. You can use a utility to flip this bit in usb stick firmware, which decides in what mode this usb stick is going to work. One of such utilities is a Lexmark provided utility for their sticks, but it works for many other sticks as well.
When a usb is in HDD mode, then it shows in operating system as hard disk.
It is a huge difference between these modes, as some computers will boot from usb in removeable mode, but not on HDD mode and others vice versa.
Another huge difference is that when usb is as removeable media, when it is partitioned by TinyCore usbinstall zip option, the second partition (fat32) will not be visible in Windows environment, because Windows treats removeable media as one partition. Only the first partition 16M will be visible. When this usb is in hard disk mode, the second partion will also be visible and show in Windows, allowing for easy backup of \tce or storing other content there. This may not be huge for those who do not use Windows, though...
If a usb stick you buy can be flipped to HDD mode, then it is a huge advantage and I have been buying only such recently, but you cannot tell before you test it...