did you try Windows clone apps or *nix clone apps? I'm fairly confident that *nix 'dd' command or clonezilla would be able to successfully clone the hidden partition SD card to another card.
EDIT: Thaikhoa already answered 'dd' will work. Try the bootable USB image of clonezilla to clone your SD card if you don't have a PC with ubuntu etc. already on it.
EDIT 2: also be aware that there may be a bug with SX OS 2.6.1, OFW 7.0.1 and hidden emuNAND partitions - they won't boot if emuNAND is enabled. A few people had mentioned their new SD card installs with hidden partitions would ''black screen boot'' and only fully load SX OS when the emunand was disabled. But it did work when they created emuNAND as files on their FAT32 formatted SD cards.
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I just said Fuck it with emunand!!!I updated my system nand so I can link my account now that's finished I used my email and still not banned!!!! Which is cool and now all 7.0 xx games work and gonna back up my nand then update from now on using choidjour