It's not fake in a standard sense. The fake ones have a flash controller that retains X amount of data before it "wraps". I've seen my share as I investigated several insanely priced drives, that promised terabytes for pennies and they typically had just some gigabytes of actual storage.
This one however just disconnects itself from USB after couple of seconds of sustained write. I tried writing stuff on it directly with dd and tried to make a note if there's some threshold after it dies but no, 500M-2G of continuous writing and it dies. Curiously it can be filled further with small, random writes.
It has the exact USB ID of earlier bought black one, which has worked for years now.
