To anyone who's still having issues flashing their box. If you have followed the idiots guide to sucmnsee image then right at the beginning there is a list of compatible memory sticks, at no point does it say about using a cheap unbranded memory stick.
Just for the record I have used sandisk cruzer everytime when flashing a box with zero issues.There has been no need to format it when it comes straight out the packet, just connect to your computer and drag the zgemma folder across into the root of the memory stick, pop into the back of the box and viola! I have used 8gb,16gb,32gb,64gb and the 128gb to flash boxes! all of which can be purchased cheaply from popular high street stores.