This guide is probably obsolete, use this instead. Just drag your otp.bin to your browser window and it will compile it for you, I'm leaving the original guide below for those who likes to DIY.

Original post:
Hopefully this guide should silence the whiners

Before we begin I have to say this is my very first guide that I made from my experience and information from other Temp members, and English isn't my primary language so I might make mistakes. If you find any just tell me and I'll try my best to correct them. (The screenshot in the spoiler was taken in OS X with wineskin because I'm lazy, this guide is for Windows only)

So you just dumped your OTP and wondering how do you compile A9LH for your 3DS? Here's a guide to instruct you how to compile and install the payload on your device. This guide assumes you know the basics of 3DS homebrew and Windows command prompt,and just stay away from this if you don't - menuhax is good enough for most people IMO. (I am serious)

DISCLAIMER: Any modifications to your 3DS are done at your own risk. I am not responsible for any bricks that may occur during this process (use your common sense and read the guide carefully)

0. Requirements:

• arm9loaderhax source (https://github.com/capito27/arm9loaderhax), it includes all the file dumps you'll need, except your own OTP
• miniPasta (https://github.com/d0k3/MiniPasta/releases , N3DS only)
• OTP.bin (DO NOT use dumps that are not from your console or the one included with the A9LH source, you WILL brick your 3DS, guaranteed.)
• Python 2.7.11 x86-64 (https://www.python.org/downloads/windows)
• PyCrypto (http://www.voidspace.org.uk/python/pycrypto-2.6.1/pycrypto-2.6.1.win-amd64-py2.7.exe)
• Make(http://gnuwin32.sourceforge.net/packages/make.htm)
• devkitARM (https://sourceforge.net/projects/devkitpro/files/Automated Installer/ , part of devkitPro)
• Your brain

1. Preparation

1. If you have an existing install of Python 3.x/32-bit 2.7.x, remove it first
2. Install Python 2.7 x86-64, make sure you install "add python.exe to patch" sub feature during installation (it's not set by default)
   
   Spoiler

   
3. Install PyCrypto
4. Install devkitPro 1.6.0, you will be be presented with tons of packages but the only ones we're interested are under devkitARM, simply uncheck everything else.
   
   Spoiler

   
5. Install Make, you should download the file with md5:8ae51379d1f3eef8360df4e674f17d6d

2. Compile A9LH

1. Extract the A9LH source to any directory
2. Copy your OTP.bin to the data_input folder and overwrite the one that's included with the zip file
3. Open a CMD window (Shift+right click on the explorer window or cd into it manually)at the root directory of the source files, type "make" (without quotes) and enter.
4. Wait for a minute or so, a data_output folder will appear and there should be no errors
5. Copy the arm9loaderhax.3dsx file from the newly created folder to /3ds/ on your SD card (the installer is built specifically for the 3DS you dumped its OTP from, if you want to install A9LH on more than one 3DS you will to recompile the payload with their respective OTP.bin files)

3.1 Installing A9LH

1. Ensure you have a dump of your SysNAND before you continue
2. Enter hblauncher using an entry point of your choice
3. Run arm9loaderhax.3dsx (see below if you're stuck on "exploiting arm9")
4. The payload will be installed to your NAND and your 3DS will then be rebooted to black screens afterwards. Don't panic, turn off your 3DS

3.2 "exploiting arm9" workaround (required for n3DS, not sure about o3DS)

1. Download and copy the miniPasta 3dsx to your SD card
2. Run miniPasta, the screen will turn black for a few seconds and you will be kicked back to home menu afterwards
3. Re-enter hblauncher and try running the A9LH installer again

4. Testing the payload + conclusion
There's a test binary (forgot who made it) that will power off your 3DS upon pressing any buttons except ZL, ZR or home. Simply copy it to the root of your SD card, wait for a couple seconds and press a button. If your 3DS powers off, then A9LH is successfully installed and woking correctly (congrats). If your 3DS powers off the moment you turn it on, check if the file is named "arm9loaderhax.bin" and placed in the root directory, if it power led stay on and won't respond to button pressed then your 3DS is probably bricked
If you want a cold boot (permanent) CFW (the reason to get A9LH in the first place), check out @Aurora Wright's ReiNand fork. She already documented it very well so I'm not going through it in this thread

FAQ
Q: I'm getting "python: command not found"
A: Make sure you select "add python.exe to path" during installation, alternatively you can set the PATH variable manually by entering this in cmd (Thanks @Kever)

set PATH=C:\Python27;%PATH%

Q: How to uninstall A9LH?[/SIZE][/SIZE]
A: Restore a sysNAND backup made before running arm9loaderhax.3dsx

 

[ric.]

They are, depends on your (micro)sd read and NAND write speed I believe.

Thanks for the reply but things are getting kinda spooky on my end.
The installer finished, it installed stage 1 and 2, and then the console turned off. No reboot, or nothing. It just shut off. I turned it on and the blue light turned on for a second before shutting off again. Turns out I was a dumbass and forgot to put the .bin file on the SD root.
I turned it back on with arm9loaderhax.bin on the root of the SD, and now the blue light turns on permanently but my screens are still black. Am I screwed?

EDIT: Decided to not be an ignoramus and try out the test arm9loaderhax.bin. Console shuts off after pressing any button, which I guess is what's supposed to happen? Guess I'm not bricked, but that still doesn't explain why my 3DS is doing nothing. Any help would be appreciated.

 

[Deleted member 379940]

Thanks for the reply but things are getting kinda spooky on my end.
The installer finished, it installed stage 1 and 2, and then the console turned off. No reboot, or nothing. It just shut off. I turned it on and the blue light turned on for a second before shutting off again. Turns out I was a dumbass and forgot to put the .bin file on the SD root.
I turned it back on with arm9loaderhax.bin on the root of the SD, and now the blue light turns on permanently but my screens are still black. Am I screwed?

EDIT: Decided to not be an ignoramus and try out the test arm9loaderhax.bin. Console shuts off after pressing any button, which I guess is what's supposed to happen? Guess I'm not bricked, but that still doesn't explain why my 3DS is doing nothing. Any help would be appreciated.

Do you mean the test binary? If so, that means a9lh works! Now you can install AuReiNand and cold boot to emuNAND.

 

[GoodGSam]

Do I need to be at 9.2 to install the arm9loaderhax.3dsx ?

 

[Deleted member 379940]

Do I need to be at 9.2 to install the arm9loaderhax.3dsx ?

I believe 9.0-9.2 should be fine.

 

[GoodGSam]

I believe 9.0-9.2 should be fine.

Thanks!

 

[Deleted member 379940]

Thanks!

You are welcome
I did it in 9.1 after restore my sysNAND.
Credit goes to @Xinaman .

after o dump OTP, restore to 9.0-9.2

 

[ric.]

Do you mean the test binary? If so, that means a9lh works! Now you can install AuReiNand and cold boot to emuNAND.

Yup, the test binary. I already had Aureinand running on that o3DS, I guess older versions aren't compatible with a9lh? How would I go about updating if I can't see what's on the screen - or is it as simple as just swapping files? Thanks for your patience.

 

[Deleted member 379940]

Yup, the test binary. I already had Aureinand running on that o3DS, I guess older versions aren't compatible with a9lh? How would I go about updating if I can't see what's on the screen - or is it as simple as just swapping files? Thanks for your patience.

Try upgrade your AuReiNand, overwrite all files.

Side note: did you restore your emuNAND to 9.x/10.x ?

 

[ric.]

Try upgrade your AuReiNand, overwrite all files.

Side note: did you restore your emuNAND to 9.x/10.x ?

I'll try that when I get back home.

And yes, restoring sys and emuNAND was the last step of the OTP guide.

 

[Deleted member 379940]

I'll try that when I get back home.

And yes, restoring sys and emuNAND was the last step of the OTP guide.

Need to sleep now.. And yes, nice to meet you

 

[aeroblast]

yes just same problem blue light and nothing else

I think I got it bricked.
I did tried with another SD clean with only that test payload and it does nothing even that wifi led won't show.
I did tried several things and I never have any other "show" so it might be just dead ^^

Fun fact is that I taken care with otp 256 kb

Dumping otp.bin (256 byte)...
Creating otp.bin ...
Dump otp.bin (0x100) (< 3.0): succeeded!

Press B to return, START to reboot.

I used that "online" compiler maybe that weird I should have made it myself tss.
I had no errors about hash etc.
It installed fine all alone

So well by luck I have a second 3ds motherboard cause I always stock parts but still if there a solution of this cause maybe that a not brick but eheh I really doubt of it ^^

There is a not unsubstantial chance you're bricked, sorry. Maybe go for a hardmod?

 

[VaiCorinthians]

I'm available to compile

 

[Baoulettes]

There is a not unsubstantial chance you're bricked, sorry. Maybe go for a hardmod?

I never know how to do so and I know no one in france that can do that ^^

 

[Xinaman]

Well, I keep getting this error. Any ideas? I kinda need this done quickly.

FIRM0 done!
FIRM1 done!
Traceback (most recent call last):
  File "common/sector_generator.py", line 1, in <module>
    from Crypto.Cipher import AES
  File "c:\Python27\lib\site-packages\Crypto\Cipher\AES.py", line 50, in <module>
    from Crypto.Cipher import _AES
ImportError: DLL load failed: %1 is not a valid Win32 application.
make: *** [sector] Error 1

EDIT: Nvm, found a service that compiles it for you.

I get that error because you need to install the 32bit pycripto version.

 

[grafate]

I'm available to compile

Everyone can do it themselves now here:

https://gbatemp.net/threads/compile-a9lh-on-demand.416385/page-7

The OP added a web version. I just did it to compare and manually doing it, the python script there and the web form there all spits out the same hashes. So I would say that makes it much simpler for those who don't want to setup their computer to compile.

 

[Xinaman]

Credit goes to @Xinaman .

Thanks man, but the real credit goes to the guide =D

 

[VaiCorinthians]

Everyone can do it themselves now here:

https://gbatemp.net/threads/compile-a9lh-on-demand.416385/page-7

The OP added a web version. I just did it to compare and manually doing it, the python script there and the web form there all spits out the same hashes. So I would say that makes it much simpler for those who don't want to setup their computer to compile.

ok

 

[Favna]

Everyone can do it themselves now here:

https://gbatemp.net/threads/compile-a9lh-on-demand.416385/page-7

The OP added a web version. I just did it to compare and manually doing it, the python script there and the web form there all spits out the same hashes. So I would say that makes it much simpler for those who don't want to setup their computer to compile.

Tbh I'm just going to stick to command prompt and MAKE. At least then when it messed up I know I have no one to blame but myself and not a web server that might be messing up badly.

 

[shamalox]

I never know how to do so and I know no one in france that can do that ^^

I'm gonna make a hardmod as soon as I receive the wire and sd reader for my own bricked n3ds, so if you want help, I'll help you

 

[ric.]

Need to sleep now.. And yes, nice to meet you

It worked and it's pretty rad. I'm part of the cool kid's club now and I love it. Thank you!
Now I have a little usage question for you all - do you prefer autobooting emunand and doing your business on the SD card as usual, or do you think doing everything on sysnand is the way to go? I can see the pros to both sides - especially when playing a lot of DSiWare and GBA injects, but after so much time of using menuhax and emunand I'm still a bit squeamish about updating sysnand.
Should I go with fully updated sysnand + 9.2 emunand, or leave sysnand at 9.2 and update emunand?