Lil Za -- D.A. REDUCED Felony to Misdemeanor

The L.A. County D.A. did exactly what we told you they would do ... this morning the felony vandalism charge against Lil Za was REDUCED from a felony to a misdemeanor.

As we told you ... the stated reason for the change is that the jail phone Za broke while in custody back in January was worth less than $400 -- the threshold for felony vandalism.

But there's a bigger problem -- our sources say Justin Bieber will be charged with misdemeanor vandalism for egging his neighbor's house ... and it would look real bad to go after Za for a felony, when Justin did $20K in damage.

As you know ... Za was arrested during the raid at Justin's house following the egging incident. Cops found ecstasy and once in jail he broke the phone.