OK, managed to get this done. A couple things, firstly, after creating the hidden emunand, I think it would be possible to format the portion of the card that is still able to be used to exfat, but I did not try it, I stuck with fat32, as I heard exfat can cause problems.
I did it like this, first I created a hidden emunand.
I then took the backup of my emunand directory from sxos 2.3, and concatenated those into one nand dump, like so:
Code:
cat full.00.bin full.01.bin full.02.bin full.03.bin full.04.bin full.05.bin full.06.bin full.07.bin > /Volumes/WhereYouWantToStoreIt/emunand.bin
Using that, and boot0/1, I had most everything I needed.
I then used Hex Fiend (MacOS) to examine the raw data from the SD with the hidden emunand on it, so I could find out what goes where.
Found that the first 1023 bytes are odds and ends, skipped that.
boot0 resides at 1024-4195327
boot1 resides immediately after, 4195328-8389631
fullnand resides immediately after, 8389632-31276925952
I fought with dd for a while working with seek, but it was very restrictive since I could only a max block size of 1k, so I decided to create the full image, and forego the skipping of the initial 1023 bytes.
I opened Hex Fiend and, then opened the disk again, and took a dump of the first 1023 bytes, saving it to a file called "completeemunand.bin"
I then pasted in immediately after that 1023 bytes, boot0, boot1, and finally the contents of the emunand.bin, the file created by concatenating the contents of the old emunand files created by sx os 2.3.
Save the file you created here to your computer, then go back to terminal
Run this to restore the backup you just created to your SD card, keep in mind you will have to replace some values, this is not for novice users:
Code:
sudo dd if=/Volumes/YourVolumeName/completeemunand.bin | pv -s 29G | sudo dd of=/dev/rdisk3 bs=2m conv=noerror,notrunc
A couple caveats here, I use pv to monitor the progress of the copy, you will need to use brew to install it, the command 'brew install pv' should be enough if you have brew installed. If you do not want to use pv, you can remove the pipes that encapsulate it and the pv command itself to use it without monitoring progress, like so:
Code:
sudo dd if=/Volumes/1TB/completeemunand.bin of=/dev/rdisk3 bs=2m conv=noerror,notrunc
Another thing to be sure of, use /dev/rdisk*, instead of /dev/disk*, this will increase your write speeds dramatically, as this is the raw device for that disk.
Once DD, is done, again this will take a while, mine took around 22 minutes, then I copied everything back to my TXNAND partition that I had backed up before creating the hidden emunand.
That's it, you should be all set, all your save games etc will be there again, and everything will be as before you upgraded to 2.4, except you have a hidden emunand now.