In the past couple of days I've been developing a brand-new A9LH installer.
It loads all the needed files from the SD card (no more need to build console-specific installers), and it's really fast. Other than that, it's way safer than the original one, as it does the following checks:
- Checks that it's able to encrypt FIRM partitions properly
- If you have a New 3DS and you're doing a first install, it validates your OTP. Sadly I have no way of validating the OTP on an Old3DS.
- If updating from A9LH, it verifies that the NAND keystore is the correct one (just in case) and that FIRM0 is correct before using it.
- Hashes the secret_sector, FIRM0 and FIRM1 from SD (if needed) to verify their integrity.
- Checks that stage1 and stage2 don't exceed a maximum size.

How to use:
- Copy the 3ds folder and the .dat if making a first install, and run the program from a vulnerable firmware; or load the .bin using A9LH itself. Press SELECT for a full install, or to update A9LH if booting from it.
- If you already have A9LH and are thus updating, copy a payload_stage2.bin (which was originally named stage0x5C000.bin) and a payload_stage1.bin to the a9lh folder on the root of the SD.
- If doing a full (first) install, you also need to copy these files to the a9lh folder: firm0.bin (which was new3ds90.firm), firm1.bin (which was new3ds10.firm), secret_sector.bin (only needed on Old 3DS) and your personal otp.bin.

Thanks go to everyone in #cakey on IRC, to delebile for his A9LH implementation, and to StandardBus who hardmodded my consoles and made this possible. Code for writing to the screens is from CakesFW.

Download: https://github.com/AuroraWright/SafeA9LHInstaller/releases

 

Waits for @Plailect to include this to his excellent guide.

 

THIS might make me switch to A9LH. Still not sure yet.

 

So all that's necessary is that installer and the files if doing a first time full install? With the OTP, that still means downgrading to 2.1? How stable is this for N3DS?

 

Waw excellent work! That will help a lot of people!
Going to add this to your new payload chaining feature

 

-snip-

 

For new installs and for A9LH updates

 

Yeah but how reliable exactly is it? I mean this got to be better than the web installer right?

 

You still need to compile stage1 and stage2. This requires no input files except for the source code, but the A9LH forks around haven't been updated for this.

 

Wait, the stage2 only update will allow me to get the ScreenInit??
If so you are a god!