A Pretty Brief History of the 3ds Hacking/Homebrew Scene
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3/2011
the 3ds launches in the west and the famous 3dbrew.org wiki site launches in tandem, which would be the main info hub for 3ds RE for the length of the 3ds's lifespan. Most DS mode flashcarts were quickly fixed to run in DS mode on the 3ds. These carts would periodically be patched until firm 7.0, after which, Nintendo gave up worrying about them.
6/2011
First 3ds roms dumped
9/2011
crown3ds
teases a promising video of a flashcard that would have been the first warez enabling solution for 3ds. What we actually got was an Engrish website forever promising: "We are in progressing ... 72%". A meme was born, and a dream died.
2012ish
It is believed Neimod's hardware RAM dumping and subsequent internal research (#3dsdev/3dbrew.org, yellows8 and friends) lead to the first userland (OOT) and a9 exploits. Teasers like IRC chat logs and the following popped up.
https://gbatemp.net/threads/3ds-hack-we-hacked-it.339271/
11/2012
3ds SOC decapping fundraiser started by 3dsdev insider gshock/jl12 to find out the system's secrets and supposedly get it hacked faster. GBAtemp community raises $2300 before gshock disappears with the money, presumably to a resort in fiji with Gateway execs.
8/2013
Gateway released. The 3ds is offically hacked and piracy begins. They continue to be basically the entire "homebrew" scene for the next year and a half. There was, however, some basic arm9 homebrew possible via mset exploit + p3ds (rsaVerifySHA256 a9 sploit), but it was limited to just bare-metal stuff like ram dumpers, tetris, pong and the like. It was less impressive than even DS homebrew (and publicly, nobody knew how to properly harness the a9's power like nowadays).
1/2014
brickgate/brickway - infamous scandal where Gateway
releases a firm that intentionally bricks user 3ds's that run their software on GW clones like R4 gold Deluxe and Orange3DS. Even some legit users get caught up in Gateway's spiderweb of bricks. Gateway did offer to fix those units.
3/2014
citra - first commit. the gold standard of 3ds emulators for the PC is born. Wouldn't really hit its stride until 2016, a testament to how complex a system the 3ds is.
11/2014
Then the giovani/palantine cfw (internally made by yellows8 and others) leak
happened, bringing the first free, closed source cfw to the masses. Limitations: 4.5, emunand not updatable, low boot rate, a bitch to install, etc. But it did run cias, and it forced Gateway to add cia support to its flashcard in a panic about a week later.
11/2014
sky3ds flashcart released. plays clean cart roms on any firmware, but no homebrew, cia's, mods, etc. Initial model limited to just 10 non-replaceable games with the manufacturer suggesting 'buy another' if you want more. Pirates consider this theft and scoff. Sky3ds eases its restriction and releases a 'blue button' card without the game limit.
11/2014
ninjhax userland (1st sane hb environment) and ctrulib make their triumphant, morally centered debut shortly after palantine.
ntr cfw released - plug-in based a11 kernal cfw that adds many cool features like RAM poking and 3ds -> PC video streaming (2016).
1/2015
Gateway cracks 9.2 and updates its flashcard to the OMEGA series. Genius yifanlu posts
detailed blog REing the GW memchunkhax/firmlaunchhax combo and teams like SALT, roxas75, and patois quickly implement it.
2/2015
rxtools released. 1st legit emunand/multi-tool implementation. anti piracy.
5/2015
pasta cfw released after sig patches leaked on pastebin (hence the name). Combined with patois open source mchunkhax/firmlaunchhax (brahma) this resulted in the 1st open source cfw. no emunand.
5/2015
rxtools patched with above sig patches by ahp_person (appletinivi). roxas does not approve, throws fit.
6/2015
roxas gives in, released rxtools source, adds sig patches officially. quits scene.
Rxtools goes on to be the "it" cfw for the next several months, despite being kinda sloppily coded and a risk to inexperienced users with its dangerous arm9 power-user features built-in.
7/2015
ninjhax2x released. App takeover, rom hacks, and other nice things too numerous to detail.
8/2015
tubehax - primary userland exploit that takes advantage of the 3ds's otherwise useless youtube app. An excellent primary entrypoint. Unfortunately patched a couple months later.
ironhax - first secondary userland exploit - one that requires a primary (like tubehax) to install.
reinand - first full featured New3ds cfw.
9/2015
menuhax - secondary home menu exploit that allows boot time userland execution. Fantastic when paired with cfw launchers save for the annoyingly unreliable *hax bootrates on 9.2. a favorite among homebrew peasants, and the sworn enemy of the late Margen67
browserhax - primary browser exploits for old/new 3ds that would be updated on and off over the coming months.
12/2015
sky3ds+ released. bypasses cart-based AP in recent games and adds filesystem-based game loading among other features.
12/2015
32c3 hacker conference - snshax, arm9loaderhax, memchunkhax2, ntrcardhax revealed. Userland exploits menuhax, and ironfall were updated too.
1/2016
10.x downgrading to 9.2 released. steveice10 implements. biggest PM group in the history of GBAtemp forged in secret ;p Downgrading patched with 10.4.
2/2016
arm9loaderhax emerges, lumbering and crushing everything in its path. menuhax peasants begin their suffering.
aureinand/luma3ds - fork of reinand that took the cfw's features to a new level. The authors, aurora wright and tuxsh, had a public falling out with the original author, reisukaku, and subsequently cut all ties with him by first renaming the project from aureinand to luma3ds, then removing the fork status altogether. It is currently the most popular cfw today (9/2016).
3/2016
aliaspider
releases memchunkhax2.1, allowing downgrades to 9.2 to resume. calls it svchax for reasons only known to him. This new k11 sploit would last through 10.7.
7/2016
stupid lolcat finally reveals the dsiware firm downgrade method after hinting about it for months. This allows the 9.2 downgrading to resume yet again (given a second fully hacked system). Nintendo privately thinks it's pretty cool, ignores it. Fieldrunners sales skyrocket.
9/2016
arm9loaderhax becomes even more irresistible due to ctrnand transfer (shortens install time on both new/old 3ds) and otpless (instant new3ds install).
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I probably missed some things, but that's a pretty good start. Let me know if there are any important omissions.
The best CFW is Luma3DS 
