Yesterday I finally took the plunge and installed MIUI on my T-Mobile G2x (which I believe is the same as the Optimus 2X). However, I noticed an issue with setting custom ringtones: the "Music" app only lets me select mp3 ringtones (ogg and wav don't play in the preview and aren't selectable, and the music player itself doesn't even try to play them directly), but the system only seems to support ogg ringtones; if I select an mp3 ringtone in Music, then the ringtone doesn't actually play when I get a call.

My workaround was to convert my ringtone to ogg and put it into the /system/media/audio/ringtones directory, but I'd much rather not modify /system in order to put in my own customizations (since then I have to worry about it disappearing when the ROM updates, or if I decide to switch to another ROM or whatever - not that I plan to do that since so far I'm very happy with MIUI!).

Is there some reason the incoming call portion of the dialer only supports ogg, and some reason the Music app only supports mp3? I know that stock AOSP supports both formats in both places, but that there's also some strange restrictions on some of the media playback APIs (for example, MediaPlayer seems to support everything but SoundPool only supports wav and ogg, as I recall). Is the incoming call notifier using SoundPool for some reason?

Clock seems to support my (10-minute-long) mp3 alarm sound, at least.