That seems to be a timing thing. The Windows Device Manager's tendency to open and close the interface when the chip reboots means you have to press the Trinket's button at just the right moment.
It seems to take some experimentation, but you want the reloading sound to occur just before the Arduino IDE is done compiling the code. Some people say to press the Trinket's reset button just before you hit the 'Upload' button in the IDE, others have had success pressing 'Upload' then pressing the reset button.
When you void a product warranty, you give up your right to sue the manufacturer if something goes wrong and accept full responsibility for whatever happens next. And then you truly own the product.