In Re Ernest R.

SIMS, Associate Justice.

This appeal arises from delinquency proceedings in juvenile court.

The minor, Ernest R., was a ward of the court due to previously sustained petitions for second degree misdemeanor burglary (Pen.Code, §§ 459, 460), misdemeanor theft (Pen.Code, § 484), possession of a knife on school grounds (Pen.Code, § 626.10), making terrorist threats (Pen.Code, § 422), and battery with serious bodily injury (Pen.Code, § 243, subd. (d)).

On March 18, 1997, a supplemental petition (Welf. & InstCode, § 777, hereafter all references to undesignated sections are to the Welfare an Institutions Code) was filed against the minor. The petition set forth the formerly sustained petitions and alleged that his prior disposition had not been effective in his rehabilitation because the minor had damaged property and committed battery on a staff member at his latest placement. Following a contested hearing the petition was sustained.

The probation officer's report recommended a Youth Authority commitment with aggregation of the previously sustained petitions for the maximum period of confinement. At the disposition hearing the minor argued that a petition filed pursuant to section…