A9LH Guide - 2025 Edition

A simple guide to install A9LH in 2025.

Note that my English isn't that good, I'm sorry if I make mistakes.

Alright, want to install A9LH on your 3DS for whatever reason? I gotcha.

IF YOU DO NOT KNOW WHAT YOU'RE DOING, GET THE FUCK OUT OF HERE
This guide is only intended for users who know what they are doing.
I am not responsible if you brick your 3DS.

PLEASE, REALLY
I'm insisting. If you truly want CFW for daily use, go to 3ds.hacks.guide and install boot9strap.

If you want to show me you succeeded, you can email me: maylina53uwu@gmail.com or DM on Discord: maylina53_uwu
(No guarantee I’ll help if you didn’t follow instructions.)

1. Prerequisites

Any 3DS family console running boot9strap (used to dump otp.bin, we'll remove it)
A few braincells

Required Files

Soundhax audio: soundhax.com
otherapp: smealum.github.io
OTP.bin (dumped yourself, should be in /boot9strap/)
Luma v6.6: download
SafeA9LH Installer: download
Arm9LoaderHax: download
udsploit: download
safehax: download
data_input_v4.zip (search for it manually, I can't provide it)

2. Downgrade (if on newer firmware)

BACKUP EVERYTHING! (Also backup NAND with NANDManager as it'll let you do a full backup in case you horribly fuck up) Get firmware files for a version between 9.0.0 and 11.3(updates folder, not CTRTransfer) region and model SHOULD match (or you'll brick.).

Put updates folder on SD root
Install sysUpdater CIA: download
Run and press Y to downgrade

Alternate method (GodMode9):

Go to GodMode9, press the HOME Button, go to More → System info to find original system version
Get matching updates folder
Uninstall all NAND titles via Title Manager (Press Home Button → Title Manager → NAND/TWL Titles
Go to SD, select every cia file (L+RIGHT) in sd/updates Press A → CIA Image options → Install image
Reboot and verify

3. Removing Boot9Strap

Make sure you haven't done a region change or use a custom keyboard!

Boot GodMode9
HOME → Scripts → GM9Megascript → Hax Options → Uninstall CFW
Follow prompts, reboot to stock

4. Installing A9LH

Place files:

otherapp, soundhax, and boot.3dsx in root
udsploit + safehax in /3ds/
SafeA9LHInstaller’s arm9loaderhax.bin in root
a9lh OTP goes in root + merge data_input_v4's a9lh folder with the one on your sd

Then:

Boot HBL via SoundHax
Run udsploit → Start to exit
Run safehax → SafeA9LHInstaller appears
Press SELECT to install
Shutdown with any button, insert SD into PC

5. Installing Luma

Replace installer arm9loaderhax.bin with Luma v6.6’s
Boot — you should see Luma config
Enable Autoboot SysNAND (if no EmuNAND)
Reboot — you're done!

Guide by Maylina53uwu — A9LH lives on 👾