I found with an file xplorer (Astro File Manager) and found 3 files, a folder (LOST.DIR) and two xml files, (customized-capability.xml and default-capability.xml) I tried ti copy mi files like music and another kind of documents with my Jelly Bean update, and stock firmware and found unable to do that, just I could pass .jpeg files from a folders of covers pictures used to add as cover's to my albums at my Walkman app, and they really appeared in Astro. I could pass a video from my camera to the sdcard too. and now what's the relation between the three files and my examples. It's that:
PC9
6.1.4Revision-version>
ST27i
Xperia™ go (ST27)
Sony
Xperia
PM-0090-BV
Phone/Android
CARD
90
480
854
16777216
5120
5120
jpg
jpeg
image/jpegtype>
image/jpegtype>
bmp
image/bmptype>
gif
image/giftype>
png
image/pngtype>
3gp
audio/amrtype>
wav
audio/x-wavtype>
mp3
audio/mpegtype>
mp4
audio/mp4type>
I'm a medicine student so I'm not well informed about what this means, but just using my rational thought as you can see in audio "sections" comes a file format and misteriously mp3 files, appear with the "false" feature and jpeg, mp4 files appear
It continues but I need to you to read that, sustaining my hypothesis of why I can't read my mp3 files.
I need an explanation for this issue, I accept the use of sdcards as media storage but (remember when you can pass even apps to sdcars in Android 2.2 Froyo?) But this makes no sense you just can pass videos or photos?. What about the music!
Update: Sorry for my mistakes, I was typing this at night
I looked for a solution, and i found here at the forums that you have to downgrade to ICS, then install the JB rooted update, and finally use link2sd method to use your sdcard as internal memory that will help
