No it's not possible yet but I can confirm that SaltySD with Fates is a work in progress.

 

I can't give an estimate of a release, but shinyquagsire23 (creator of SaltySD) is looking into it.

 

Hype! Can't wait. Do tell when it's ready.

Hmm.. I'm quite new to this could you explain?

 

I would say NTR + layerFS is the way to go, or even NTR + this
edit: ninhax'd

 

Go to this website and search for the game you want to modify
Let's take fire emblem as an example



Scroll to the right until you see the "titleID" column and copy the number.
(this one is the titleID of fire emblem conquest EUR)



Then, if you're using OnionFS
just follow these steps:


Where <titleID> is the number you copied before.
For this game, should be
SD:/plugin/0004000000179700/OnionFS.plg
And the folder where you'll put the modified files into
SD:/OnionFS/0004000000179700/
So, if you decompress the romfs of Fire Emblem Conquest EUR and check that the files you want to modify are in a path like this
/audio/sfx/bgm.bcstm
(That's an example, I don't know where the sound are stored in Fire Emblem )

Then you also need to create, inside "SD:/OnionFS/0004000000179700/" an "audio" folder and a "sfx" folder inside it, and paste the modified "bgm.bcstm" into it,
always mantaining the original structure and adding only the files you want to change.

You would have something like this
SD:/OnionFS/0004000000179700/audio/sfx/bgm.bgm.bcstm

 

You need a decompressed CIA.
You can dump it decompressed (I think the option is in "CIA Builder Options" on the latests decrypt9's versions)
or decompress the CIA if you still have it.
Here, on the "Extract" section you have some information about extracting from CIA files.