I suppose I should speak up since the thread has been active lately.
The truth is I've attempted to update to the 1.1.2 version multiple times but I've kept hitting a wall involving the audio playback. The sound would just cut out after trying to play a sound effect or two and nothing I tried seemed to help.
About a week ago I've decided to try again, but this time I'd finally bite the bullet and stop using SDL for audio. It was simpler than I thought it would be because the engine mixes its own audio, it just needs to be fed to the hardware (but I'm kind of an idiot so it took a few days to set that up).
The previously mentioned audio issue is now gone and the audio itself sounds 'okay', but it feels off compared to the old version that was using SDL.
As for mod loading, I thought I hit another wall but it was an easy fix. Mods would work in Citra but not on real hardware. Why? Because the mod loader was inserting double slashes into file paths (ex sdmc:/3ds/Sonic1/mods//Sonic 1 Visual Overhaul/). Apparently most OSs can handle an error like that but the 3DS cannot.
Unfortunately mod compatibility is all over the place. Some work exactly like they should (Full Engine Rotation, Sonic 1 Visual Overhaul, Gorgeous Labyrinth) but others crash the game (Separate Act Themes, Sonic Forever). I'm still trying to figure out why that is. I haven't really tested them on PC yet so maybe the mods are just broken, idk.
I'll go ahead and upload what I have onto github if Saturn or someone else wants to take a look at it.
tl;dr: I've made good progress updating to v1.1.2 but it's in a very WIP state right now.
Yeah, the audio backend on the decomps is really buggy, even on PC (there's currently a bug with the 1-Up sound effect not playing fully, among other things). I actually got burnt out on the CD port for a while trying to fix audio issues (mainly music/sound effects completely stopping after time traveling).
What I eventually did to fix the audio thread on RSDKv3 was basically stub out all the audio code and replace everything with SDL_Mixer calls. This backend can be enabled by introducing the preprocessor flag RETRO_USING_SDLMIXER. It works, but at the cost of slightly longer loading times due to the API needing music files to be cached in memory as opposed to streamed from a file. This also has the side effect of crashing the game when using mods that provide higher-quality music files, presumably due to there being not enough memory. It does work with music mods that more or less use the same bitrate, though.
I was actually working on implementing the SDL_Mixer calls into RSDKv4, so I can fork, finish up the changes, and make a pull request; maybe it might fix compatibility with mods that use custom music files like Sonic Forever. Or not. I've had reports of some CD mods like
this Super Sonic mod absolutely killing the frame rate for some reason, on top of various slowdown issues. Sonic Forever apparently even caused slowdown on the Switch port for a while. While further optimizations to the decomp ports probably can be made, past a certain point, its really up to mod creators to optimize properly.