Default [Q] E: failed to mount /efs (invalid argument)

I guys, I have a Galaxy tab 2 GT-5110, it is stuck in the Samsung Icon, it also won't start in Odin (download mode), when a press power + down volume it shows the message "no command" then E: failed to mount /efs (invalid arguments), I don't have the efs back up, and the Samsung Kies doesn't recognise the tablet, pleasessss any tips?, thank you so much