How can I make MX5 (OS5.1.1.1A) recognize locally stored LRC files

i am a MX3 (OS3.6.1A) user and bought MX5 in Shanghai a week ago.
managed to install Google Play but can not overcome the titled problem.
on MX3, the file name of music file should be exactly the same as LRC file.
MX5 once recognized the lyrics (LRC file) but once I accidentally select the displayed LRC file in edit mode, it never come back even discarding the wrongly selected LRC file.
please let me know the rule of recognizing the local LRC file if there is.
file (folder) structure is same as MX3 as follows;
Music
|— cover
|— download
|— lyric

or do I have to system upgrade the phone using the same firmware?

[Self resolution]
Basic rule applies.
LRC file name should be "Artist - Title.lrc"
once you discard available lyrics on the net, even a suitable named file is locally available, you have to enter edit.
You will see the locally stored lyrics file in the list of “Choose Lyrics”

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