Can A Student Give 12thboard Exams From Two Different Boards In Consecutive Years ?

No

विद्यार्थी किसी भी बोर्ड से अनुमति (प्रवजन प्रमाण पत्र)ले कर ही किसी अन्य बोर्ड से परीक्षा दे सकता है अतः यदि आप दे भी देते है तब भी मान्य नहीं होगा।

no he can't.

no you can't.

Please do not waste other's time. You were given all clarifications earlier.

No, law cannot allow to sit in two differents boards if, u should registered you in 11 class again then only possibilities came to it 🙂