What is the test for a defendant to plead guilty to a charge of possession of a firearm with intent to endanger life imprisonment?

There must be express and specific admonitions as to the constitutional rights being waived by an admission before the trial court can accept a defendant's admission he or she has prior felony convictions. (People v. Cross, supra, 61 Cal.4th at p. 170.)

Further, as a judicially declared rule of criminal procedure, before admitting a prior conviction allegation, the accused must be advised of the precise increase in the prison term to be imposed, the effect of parole eligibility, and the possibility of being adjudged an habitual criminal. (People v. Cross, supra, 61 Cal.4th at pp. 170-171.)