Faulty implies a manufacturing defect – there is nothing “faulty” about flash memory chips reprogrammed to lie about their actual capacity. This practice is very common in the Orient. The nand flash memory chips are digitally altered using low level formatting tools. Quite a few usb controller chips are easily manipulated. The most common are found in Alcor, AMECO, iCreate and Micov families.
Software is widely available often the same software used to prepare the chips in Fabs for correct capacity. Digital alteration is commonly referred to as “Hacked” memory. Is it difficult to do?