Glad to read this, doom svn is an awesome homebrew !
If you want to take the experience a little further, using hbmenu, you can also launch the pwads.
First you will need all the officials iwads, I advise you to take those and rename them like this:
Doom shareware : DOOM1.WAD
Ultimate Doom : DOOM.WAD
Doom 2 : DOOM2.WAD
Plutonia : PLUTONIA.WAD
Tnt : TNT.WAD
Note: try to find version 1.9 of Ultimate Doom and Doom 2
Once you have them, drop them in the dsdoom folder and launch them all one after the other. when you launch them, wait for the demo to start then shut down your console, you repeat the operation for each of the iwads in order to obtain a clean tranmap.dat file.
Now that you have a clean tranmap.dat file, make a copy of the dsdoom folder and its contents on your pc and rename your dsdoom folder to "dsdoom mods", copy your new folder to your sd card.
At this stage, you have two dsdoom folders on your sd card, one for iwads and one for pwads, it is important to dissociate them because some pwads can damage the tranmap.dat file so to avoid making a new one, it's easier to create two dsdoom folders like this if a pwads damages your prbomm.cfg and tranmap.dat files in your "dsdoom mods" folder, you just have to delete them and make a copy of the ones in the original "dsdoom" folder to replace it.
Now that you have finished the pre-installation, go here, follow this tutorial and enjoy the Doom Experience !
https://gbatemp.net/threads/dsdoom-svn.364770/page-4#post-8372959