Thanks to both.
I'd like to install A9LH on my N3DSXL on which I have a NNID with a good number of legit games. But I don't want to redownload everything and saving/restoring all the saves with JKSM (it's a lenghty process, as you have to start the game in order for it to create the save data and only then you can overwrite it). Moreover, I don't think you can save NAND data (activity log, for example) for the same reason you can't dump the NAND.
I have an O3DS already A9LHed with no NNID, but unluckily you can't system transfer from N3DS to O3DS (this way I could transfer the data from my N3DSXL to O3DS, dump the NAND, format it, buying Fieldrunners, etc - with a bit of transfers back and forth I could restore my N3DSXL to it's original state, but alas!)
Thanks anyway