What is the test for reversal of a conviction for second degree murder?

When a legally erroneous theory of conviction is presented to the jury, reversal is required unless, on the record made at trial, the reviewing court can determine that the conviction actually, if not solely, rests on a legally [9 Cal.4th 328] proper theory. (People v. Guiton (1993) 4 Cal.4th 1116, 1128-1129, 17 Cal.Rptr.2d 365, 847 P.2d 45; see People v. Smith, supra, 35 Cal.3d at p. 808, 201 Cal.Rptr. 311, 678 P.2d 886 [concluding that reversal of a second degree murder conviction is required unless the People can "show that no juror relied on the erroneous instruction" on second degree felony murder "as the sole basis for finding [the] defendant guilty"].)