I would imagine conversion from Islam to Zoroastrianism carries the same penalty of death as conversion from Islam to Christianity.
Oooh, yeah. And then some. The occasional benevolent passages in the Quran (the ones the ignorati use to call Islam a ROP) refer to Jews and Christians as "Peoples of the Book" (Ahl al-Kitaab). There's no mercy for apostasy of any kind, but to a non-Abrahamic religion? Double dog death.
Correct - conversion from Islam (apostasy from Islam) is punishable by death as per the Hadiths. Doesn’t matter if to Christianity, to Zoroastrianism, to Hinduism, to atheism