[Clip+] How to go back from Rockbox to Original Firmware?

[Jiehfeng]

Sorry if this question was asked before or was in the faq, but I'm not too sure. Some songs on Rockbox always seem to skip on me. Like when I start to play them, they skip to the next song.
So I was wondering how can I go back to my original firmware, or if possible, how can I fix this issue?

[saratoga]

http://download.rockbox.org/daily/manual/rockbox-sansaclipplus/rockbox-buildch3.html#x5-280003.1.3