For the sake of the ones that are yet to return to the thread, i'll make a little summary:
(I'm not an expert, so correct me in any wrong information and i'll edit the post)
BEFORE CONTINUING, REMEMBER: IT'S NOT RECOMMENDED TO DO ANY OF THE METHODS ON THIS POST,
I CAN'T ASSURE YOU THAT ANY OF THOSE ARE 100% WORKING FIXES, DO ANY OF THOSE AT YOUR OWN RISK.
022-2812 Error Code:
A patch was already made, but it's not 100% working yet, here's how you do it:
1) Download this file: https://transfer.sh/OLf8K/arm9loaderhax.bin
2) With the arm9.bin in hands, just go to the root of your SD Card and overwrite the actual arm9loaderhax.bin that is there with the one you just downloaded.
3) Now you're done with 022-2812, but probably will get a 022-2501 error code instead. It's because of your NNID, to fix that, just go to your NNID settings and when prompted with an error message, press X + Y and then, press A to remove your NNID from your 3DS.
4) From here you have two options:
A) Remain without a NNID and use eshop normally;
B) Create a new NNID and get a new error (011-6901) that
at the moment of this post does not have a fix.
002-0102 Error Code:
By now, we have two methods for fixing that ban:
A)2 3DS Method:
This one is pretty simple, you'll need 2 3DS consoles with CFW and one of them NEEDS TO BE UNBANNED;
Disclaimer: If you do that with a 3DS of a friend, remember: We can't assure that Nintendo will not discover this and get him banned. Think twice before doing this with something that isn't yours.
Here's what you gonna do:
1) On your UNBANNED 3DS, load up decrypt9, go to SysNAND Options>System File Dump>Dump LocalFriendCodeSeed_B;
2) Get the dumped clean LFCS on Unbanned3DS-SD-Root/files9 and put it on Banned3DS-SD-Root/files9;
3) Now, on the BANNED 3DS, open decrypt9 again, go to SysNAND Options>System File Inject>Inject LocalFriendCodeSeed_B;
4) Now you're done, reboot your 3DS and enjoy being 002-Unbanned (BY NOW)
B)1 3DS Method:
Before doing this, be sure that Your banned 3DS did a System Transfer before, if not, this will not work.
So let's go:
1) Open Decrypt9 on your 3DS, go to SysNAND Options>System File Dump and do the two following procedures: Dump LocalFriendCodeSeed_B and Dump movable.sed;
2) Now open your SD root on your pc, and get the 2 files you just dumped in the files9 folder;
3) Open HxD (download it for yourself) and open both movable.sed and FCSL_B;
4) On movable.sed, copy everything except for the first 8 bytes and the last 40 (for dummys, use the indexes, you can start copying from row 00000000/ col 08 until row 00000110/ col 07);
5) Open LFCS_B, press ctrl + A, then paste your code (it must be and different code than before, if not, see step 7)
6) Now just go to Decrypt9 again and inject back the LFCS_B that you edited and you're good to go.
Troubleshooting:
7) If you did a system transfer before and your movable and LFSC are the same, you can do the following:
YOU NEED AN OLD NAND BACKUP TO PROCEED
8) Get your old NAND Backup and dump the movable.sed from it;
9) Check if the movable.sed seed is different from your actual localfriendcodeseed_b;
10) If it is, you're lucky, copy and paste it on your local friend code seed, restore your nand to your most recent one and then inject your new LFCS 
Sorry for the credits, cause i don't remember right now who discovered what, so if you want to be credited, just ask me and I put your credits
Hope i helped some souls
