She was the daughter of Phutthayotfa Chulalok, the first king of Siam, and his wife Chao Chom Manda Thongsuk (née Princess Khamsuk of Vientiane).
[1][2] Princess Chanthaburi was a daughter of Phutthayotfa Chulalok, founder of Rattanakosin Kingdom by a Laotian royal consort, Chao Chom Manda Thongsuk (née Princess Khamsuk).
The young princess was then elevated to Chao Fa ranks by her father, as her maternal grandfather was a ruler of a vassal kingdom.
Seems to be equal, but in fact the king had sworn to Princess Bunrot, that he wouldn't allow any son from another woman to occupy a position equal or even higher than any son born from her.
Prince Klang later known as Prince Mahamala, was bestowed the title of Krom Khun Bumraap Porapuksa by his half-brother Mongkut, then elevated to Krom Phraya by Chulalongkorn.