Unfortunately dumping the NAND with a programmer is not enough, as you're missing all the console specific encryption keys that you would have gotten through a BootMii dump. However, Error 003 might be recoverable through other means. I would give these WiiBrew articles a read and see if this would work for you.
https://wiibrew.org/wiki/Error_003 |
https://wiibrew.org/wiki/SaveMii_Dongle