I'm terribly sorry. I can't offer further technical assistance that directly solves or fixes this problem. I believe your 'missing audio in DS(i) mode' bug could be somehow related to these 'nonworking touchscreen in DS(i) mode' bug found in these other n3DS and o3DS systems.The audio works on the Home menu and in 3ds games without problems.
In DS games there is no sound, also I have to try to run the games several times (sometimes it works and sometimes it only returns me to the Home menu).
Previously my console did not connect to Wifi, but after the tutorial it seems that this problem has been solved.
Here is a video of the problem.
-snip-
Thank You!
There was one other person I've come across who had an o3DS that had a somewhat similar issue where the audio no longer works in both 3DS and DS(i) modes.
* (As of writing this in 2020)
Since the oldest of the Old 3DS are pushing almost 10 years of active use, it's not surprising that more people are reporting their systems exhibiting some of the strangest behaviors that can't be fixed with available homebrew software repair methods. Circuitry aging is catching up and afflicting those traces, caps, resistors, IC chips, and all the other little SMD/SMT nuggets found throughout the motherboard. We're going to be left in the dark until there's someone who has hands-on experience with these DS(i) mode bugs and manages to fix, document, & share their findings.
Last edited by TurdPooCharger,