What is the burden of proof to prove the issue of withdrawal?

Furthermore, appellant did not request such an instruction at trial. He cites numerous cases informing us that his burden was merely to raise a reasonable doubt in the minds of the jury of his "withdrawal." But he cites none asserting that CALJIC No. 6.20 or 2.90 fails to make this clear. We find no sua sponte duty to give what we see as a pinpoint instruction linking the burden of proof to the specific issue of withdrawal. While the trial court is required to "instruct on general principles of law that are commonly or closely and openly connected to the facts before the court and that are necessary for the jury's understanding of the case," (People v. Montoya (1994) 7 Cal.4th 1027, 1047, 31 Cal.Rptr.2d 128, 874 P.2d 903), in the present case it did that. The jury was instructed on the issue of withdrawal (CALJIC No. 6.20) and on the burden of proof (CALJIC No. 2.90). It was also told to consider the instructions as a whole, (CALJIC No. 1.01), and that "each fact or circumstance upon which [an inference of guilt] necessarily rests must be proved beyond a reasonable doubt." (CALJIC No. 2.01.) In addition, while arguing the firearm allegation, the prosecutor told the jury "this [allegation], like everything else, must be proved beyond a reasonable doubt...." The jury could not have been confused.