Also already stated. You're late to the party dude.
To quote what I typed earlier AGAIN;
'Ah, I now see that this is a different situation than a standard brick."
I know your already aware of the situation now, but just to clarify in case someone finds this thread in the future
flashing a bad nand/cia or whatever will result in a
blackscreen brick(console will power on, but screen remains black)....only way to recover from this type is with a valid working nand dump from that specific console, this type of brick can be recovered using a hardware nand mod and a standard computer windows/mac etc, by writing a valid nand dump back to the nand as the nand is still fully functional, the FW is just not usable by the 3ds
old launcher files such as R4 gold deluxe,3dslink,orange 3ds, FW's 3.1,3.2, and GW 2.0b2, these launcher are known to brick consoles by purposefully locking the nand which results in a bootrom error,this is often referred to as a BSOD(stupidly as B could stand for blue or black, screen of death, but is mostly referring to blue) the only way currently (and probably ever as they don't really happen no more unless someone purposefully hunts down an old FW, so nobody is likely to develop any new methods) is using a raspberry pi A or B (not the A+ or B+) and a hardware mod to manually unlock the nand, this cannot be done really on windows as the nand has to be communicate in via a sort of vendor mode to issue the unlock command, i dont think there is any SD readers that allow this level of communication to the SD interface from within windows, anything like that would be dependent on specific card readers and custom made drivers.....which would be a lot of effort when the raspeberry pi/arduino allows this kind of feature to be used with their default hardware for relatively cheap
TL;DR black screen can be fixed with SD reader and a valid nand backup, blue screen brick needs a raspberry pi, and in most cases will not need a nand backup