i need far manager and other things to change menu icons for my k790i and want a detailed steps to use this.please help me.thanks in advance

It is actually now compatible with the k800i i dont have it as i sold my k800 but if you have a google for DB2020 SEFP you'll find it, or you could google the man that makes it "den_po" either way you'll find it quite easily

Note: only a write only breakin loader was released so you'll not be able to backup any original files but im sure there's a DB2020 firmware decompiler you could use to backup ALL original file's, its found in the same place as den_po's version of SEFP (thats the name of the pluggin for FAR by the way)