no, you should use soundhax
That's what I said.
I will be using soundhax to prepare the CFW on my unupdated 3DS and use it as the "Source" 3DS for the DSiWare Save Injection
Either way I did hear about ntrboothax from the site but I happen to own Four Swords (I got it legit when they were giving it away for the anniversary, had it installed since) so I can do that for the DSiWare Save Injection. I will just simply exploit my old one (the unupdated one) with soundhax, system transfer from my main 3DS ("Target") to that one so the "Source" 3DS will have Four Swords, make sure my "Target" 3DS is formatted and follow the steps on the site.
So from there I will have a 3DS that is basically blank with nothing but the exploit (and default software) left (The one that acted as Source) and my 3DSXL that I want to use will be back to having the NNID and everything associated to it? But now both of them will have the CFW.
Did I skip anything?