This tutorial will allow you to install Browserhax then HomemenuHAX & finally launch a Rxtools CFW from coldboot.
To make a full working tutorial, I tried to gather all informations possible around GBAtemp.
This tutorial works for me, i own a New3DSXL EUR in 9.0 firmware, it sould work until 9.2​

Video tutorial made by @Ericzander​

Requirement :
- A 3DS, 2DS, New3DS between 9.0 and 9.2
- Use a theme at leat once
optional :
- Emunand with a Manager installed on it
- blank N3DS/3DS & Blank SDCard

BrowserHAX

1) Download Smea’s starter pack: #LINK and extract the files on your SDcard.
1.1) Download the modified MenuHAX : #LINK , put in SDcard/3DS & overwrite.
2) If you have never use a theme on your 3DS, go into the theme setting & wait for the preparation to finish then return in home menu.
3) 1st you have to turn off the Wi-Fi, next open the 3DS camera by pressing L & R at home screen, touch the QR icon at bottom-left of the bottom screen and scan the QR CODE :

then open the internet browser when the message appear.
4) The connection will fail since there is no internet, press home and activate the Wi-FI. Launch again the internet browser and wait until the Homebrew Launcher is launched. The bottom will flash into different colors, yellow, gray, blue & red.
For O3DS user : When you launch the internet browser you have zoom-in several times then go in the upper-left. You will see a slide bar, you have to click a the end of the bar. You may have to retry if it doesn't work, you also try to wait 20 seconds before clicking & hold the A button when you click on it. IT CAN BE REALLY HARD TO GET INTO HBL !!!!
5) Once you are in the Homebrew Launcher browse through the homebrews and select MenuHAX 2.0.[/code]

MenuHAX 2.0 BY YELLOWS8 & EDITED BY legofan623 (READ ALL FIRST !!!)

6a) Now that you are are in MenuHax manager, select “Install” and MenuHax will be installed. Press A to go back at select screen & quit if you don’t need anything else.
6b) You can configure the button to use to boot MenuHax, select “Configure/check haxx trigger button” & choose the option that you want to use.
- Type1, Boot MenuHAX with selected setting
- Type2, Boot Sysnand with selected setting
- Type 0 is default, L to boot MenuHAX

Exemple :
- Autoboot MenuHAX type1, select type 1, touch the bottom screen.
MenuHAX will autoboot when the 3DS is turned On & if any button is hold at boot the 3DS will boot into Sysnand.
- Autoboot MenuHAX type2, select type 2, hold specific button or combo button then touch bottom screen. HomeHax will autoboot, if you hold your specific button or combo button the 3DS will boot into Sysnand.
- Non AutoBoot MenuHax, select type 1 & hold specific button then touch bottom screen if no button is hold, Sysnand will boot if specific or combo button is hold MenuHAX will boot.

6c) You can change the boot screen image by choosing “configure MenuHAX boot logo”.
You will a 800x240 (3D work, so non 3DS logo, use twice the same picture (400x240)) png file named “imagedisplay” & put in SDcard/3DS/MenuHAX_manager then select “configure MenuHAX boot logo”
6d) If you want a custom theme on your sysnand with MenuHAX, put the body_lz.bin and BG.CWAV into SDcard/3DS/MenuHAX_manager & choose “Install custom theme” then select “install” for install MenuHAX
6e) If you want a basic theme on your sysnand with choose “Setup a basic color theme” then select “install” for install MenuHAX

CFW - RXTOOLS

This custom firmware will allows you run .CIA.

1) Rename the boot.3DSX in your SDcard into bootHBL.3DSX
2) Download Rxtools boot.3DSX (updated) :
TYPE1 : https://gbatemp.net/attachments/rxtools-rar.26153/
TYPE2 : http://www.mediafire.com/download/ydvv3aa3mk1kuy7/rxtools.3dsx
Use Type1, if you have a low boot rate, try Type2. If it's still not working try CTRbootmanager
3) Put the Rxtools.3DSX of the extracted zip in the 3DS SDcard root
3.1) Rename the Rxtools.3dsx to boot.3dsx
4) Download
- Rxtools older release : https://mega.nz/#!KQ1HVDLZ!TJhiM4zQlknFSqdkDDf8oGMHaNod6-WbR_ggznC8b3c
- Rxtools nightly build (unstable use older release if rxtools does not work correctly): https://lavanoid.github.io/ or https://www.dropbox.com/sh/blmecish9rb1r87/AACOS5s8u0xucXy59vZk6i1pa?dl=0 (last one)
5) Extract rxtools folder from Rxtools archive to sdcard root.

ALTERNATIVE METHOD if you want to install multiples CFW and use Homebrew launcher at the same time

1) Rename the boot.3dsx into boot_hb.3dsx
2) Download Rxtools nightly build : here or on dropbox
3) Extract rxtools folder from Rxtools archive to sdcard root.
4) Download : CTRBootManager
5) copy the two files inside the archive to your SDcard root

FOR NEW3DS USER :
6) Download Reinand 2.1 CFW
7) In Reinand archive find firmware.bin (in rei folder) the MD5 must be 006559E2567DC7DF6C0F1AF17EDD9CE8
7.1) extract it to rxtools/data (you may have to create it)
7.2) rename the firmware.bin into 0004013820000002orig.bin for old release of RXTools or 0004013820000002.bin for latest release of RXTools.
8) Put back SDcard to the N3DS
9) Power on your New3DS with your homemenuHax method (L or not)
it should boot Rxtools and Emunand.

FOR O3DS, 2DS USER :
older release :
DL link : https://mega.nz/#!KQ1HVDLZ!TJhiM4zQlknFSqdkDDf8oGMHaNod6-WbR_ggznC8b3c
6) Find the firmware.bin ont the internet, the MD5 MUST be A9DCD99A360E8629810F8ED08403D746
7) Put the Firmware.bin in Rxtools/sys
8) Put back SDcard to the O3DS
9) Power on your New3DS with your homemenuHax method (L or not)
10) For the first boot you will see the installation suite, wait until the 6 square are full.

newer release, you will need Python installed on your computer :
6) use the "cdn_frm" file in the "tools" directory of the rxtools to generate a folder named "firm"
7) Put the folder in rxtools folder
8) Put back SDcard to the O3DS
9) Power on your New3DS with your homemenuHax
10) For the first boot you will see the installation suite, wait until the 6 square are full.
it should boot to emunand automatically

You can use other CFW if you don't like Rxtools
For CakesFW
CakesFW thread : https://gbatemp.net/threads/release-cakesfw.391200/
CakesFW boot.3DSX : https://www.dropbox.com/s/eigz92hojmnelrs/CakeBrah.zip?dl=1
Take the Cakes.3DSX , rename it Boot.3DSX & put in SDcard root

For Reinand
Reinand thread : http://gbatemp.net/threads/source-release-reinand-n3ds-cfw.394309/
Reinand boot.3DSX : https://mega.nz/#!dp4knbDT!TDKIFrEbbJG2g1R4m7b9TC_JE63Fl7BTS0aKdYnALsw
Take the Reinand.3DSX , rename it Boot.3DSX & put in SDcard root

Install a CIA manager : O3D, 2DS ONLY & Unlinked NAND ONLY ! (for the moment)
- boot your 3DS
- Hold L at debug screen toget into Rxtools menu
- go to advanced tab (press right)
- Select "Install FBI" & choose "emuNAND" by press the Y button
- Press the B button, a message should appear.
- Keep in mind the region of your 3DS & number of the line "Version of TMD : XXXX"
- Power off your 3DS and put your SDcard in your computer
- In the rxtools archive of this guide or any nigthly go to Release/Tools/fbi_injection/Your 3DS Region/The version number of TMD and copy the 2 files at the root of your SDcard.
- Put Back your SdCard into you 3DS boot to RXtools menu
- Go to Advanced > install FBI > choose Emunand & it should install FBI on your Emunand
- Keep the files by pressing B on the follow screen.
- Boot emunand and launch the safety app (yellow triangle)
- it should launch FBI
- Instal either big blue menu or any of your CIA.

More informations :

- if you have trouble to get into emunand after boot Rxtools follw this order of installation :
- Format SDcard
- create emunand : put launcher.dat & use the web browser to get gateway menu, select format
- unlink emunand : go to Settings > remove your SDcard from 3DS > orange icon (bottom-right) > format
- activate theme on sysnand : put back sdcard, use a theme
- run browserhax : read guide
- install themehax : read guide
- install rxtools : read guide
- launch rxtools : read guide
- update emunand in rxtools : go to setting check that there is RX-E before firmware, update in settings
- reboot

- If want you want use differents Boot.3DSX at the same time, maybe a CFW and Homebrew Launcher, you can install Ctrbootmanager. It allows to choose which boot.3DSX or any files to boot when you switch on your 3S with HomemenuHAX.
Link : http://gbatemp.net/threads/ctrbootmanager-3ds-boot-manager-loader-homemenuhax.398383/

- If 3D is broken just close your 3DS and open it should fix the 3D.
- If you want to boot in sysnand with homemenuhax autoboot just hold any button at boot.

- If you have a black screen tell in the comment what is the last thing that appear on your screens
- if nothing work i suggest you to format your SDCard & retry every step of this guide, do not skip any of them, some old files on your sdcard may prevent the good behavior of this guide.