Ok, I will try to help you. I at first was getting invalid firmware image as well. What I did at first was just download http://code.google.com/p/cmp738a/dow...s4.7z&can=1&q=
this and rename it to update.img and transferred it to the disk drive of the craig 7" tablet. Well, you don't actually do that. What you do is download the file from here http://code.google.com/p/cmp738a/dow...s4.7z&can=1&q=
and use 7zip to extract the file to an .img extension. Then, you rename the .img extension to update.img
Once you do that then transfer the file to the tablet, and unplug the USB drive then it will update correctly. If you need anymore help I'll try to help.