New 3DS w/ 11.3.0-36U + Luma3DS (v6.6)+ A9LH = Working
Just to help some folks out, I would like to share my personal experience w/ updating to 11.3.0-36U.
Prior to updating my new 3DS, which has A9LH, to 11.3.0-36U, I was using a super old version of Luma3DS (some version that came out in mid-2016). Right after the update finished, my 3DS rebooted into a black screen. Immediately, I sense something was not right so I started panicking. I tried rebooting several times with and without the same microSD card but nothing worked. I tried using a different card and that didn't work either. Then I did some digging and found that 11.3.0-36U was the source of the issue, so I decided to follow the A9LH guide posted on
https://3ds.guide/updating-a9lh to update A9LH and Luma3DS and got my 3DS to boot up again.
A few things that I had to do different:
In section 1 of the A9LH guide, it says to, "Copy arm9loaderhax.bin from the Luma3DS .zip to the root of your SD card, overwrite existing files". the overwrite for me didn't work on my copy of Windows 10 Insider Preview build. So, I manually deleted arm9loaderhax.bin from the root of my microSD card and copy arm9loaderhax.bin from the Luma3DS .zip to the root of my microSD card.
Also, I deleted the config.bin file located the luma folder on my microSD card.
Link:
Luma 3DS -
https://github.com/AuroraWright/Luma3DS/releases