Repairing flash memory cards to their real capacity is not as easy as it is for fake usb flash drives or mp players. TechChips at FlashChipTech released a report you should read:
Fixing Fake SD SDHC Cards, Is It Possible? What Are The Problems And Challenges? What Software To Use To Test For Flash Memory Fake Chips. Is There A Free Download To Check Flash Drives And Memory Cards Size
It’s probably the best chance you have to repair hacked memory cards and understand the challenges you face.