Alright. So, you're on 2.1 on N3DS without a NAND backup. If you absolutely do not have a NANDmin.bin anywhere, here's your only option now:
9.2.0 ctrtransfer
Note that if you already have .tik files in the /files9 folder on your SD card, you should skip steps 1-6 in Section II. Other than that, just does what it says.
After you do this, you should be able to continue the guide. However, this is a rare scenario that rarely comes up, so it is slightly less explored territory. However, it's all you can do now, and it's still not that dangerous (actually, you have arm9loaderhax installed now, so you can't really brick anyway).
Let me know how it goes. And please, always back up your NAND, kids
[Note to people who may come here from a Google search, do not do the above, unless you have no NAND backup. This was a special case.]