Totozorz,
my usb has
iCreate controller chip. Therefore, I used
iFormat utility. after finding out that its capacity is 4GB, I used iFormat version 1.32 to format it. At the end, I succeded to format it and now I have a 3.5 GB (not 4GB) usb altnough I bid for a 8GB
First you have to know the controller chip type. There may be some utilities if you can not open it.