Need help please iPad mini2 with nand error 40

[Adie67]

Hi all I'm new here I have a problem with a error 40 in iTunes, I have removed the nand chip from a iPad mini 2 32gb, I haven't ripped any pads off the logic board or the nand chip, I've removed all the black glue using my hot air station at 180 degrees, I've rebelled the nand chip with new low melt solder, I've erased the nand chip placed it back into the iPad and tried to restore it but I'm always getting error 40, I made a backup from the nand chip I have changed the sn, I've hit the tab which says fix invalid sn but nothing is working for me, please any help would be really appreciated as this error 40 is driving me mad, thanks again.