So, my friend was trying to install Luma on his Old 3DS. He was at the SysNAND Transfer Options and the Auto option wasn't working so he hit the Forced option. Everything was going fine until he got to the SafeA9LH Installer, when he hit the button to shutdown his system it wouldn't turn back on. Now, whenever he tries to turn on his 3DS the blue light goes on, then off. He's tried holding Select+Power, and he has his SD card in. He's also tried holding L+R+Up+A+Power and the same thing keeps happening. Is it bricked?
See if a file named arm9loaderhax.bin is on the root of his sd card, if yes it might be bricked, otherwise you need to get it...
Pretty sure that was the problem. The file is nowhere on the SD card. Transferring it right now, fingers crossed.
If the above doesn't work try deleting the extdata located in Nintendo 3DS>32 characters>32 characters>extdata>00000000 and delete "0000008f" folder(USA console). Maybe that had something to do with downgrading(which is obsolete now) but I remember it turning on and off like that even when I had the arm9loaderhax.bin on the root of the SD card or if the NAND side of Luma wasn't configured to boot without an SD card it did that as well. Edit: I see you got it now.