When a firstborn sells his extra share of the inheritance before the estate is divided, the sale is binding. For the firstborn's extra share is distinct, even before the estate is divided. Therefore, if initially, the firstborn divides a portion of the estate, either landed property or movable property, and accepts the same portion as an ordinary son, he is considered to have waived his right to an extra portion with regard to the entire estate. He receives only an ordinary son's share of the remainder.
When does the above apply? When he did not protest. If, however, he protested against his brothers and said in the presence of two witnesses: "Although I am dividing these grapes equally with my brothers, I have not waived my right to the firstborn's share," his protest is significant and he is not considered to have waived his right to the other property.
Even if he protested with regard to the division of grapes while they were still attached to the earth, and yet agreed to divide them equally after the harvest, he is not considered to have waived his right to the other property. If, however, the grapes were pressed, and he divided the wine equally with them and did not issue a protest when the wine was made, he is considered to have waived his right to the other property. To what can the matter be compared? To a person who issued a protest when grapes were divided but then divided olives equally, in which instance he is considered to have waived his rights to an extra portion of the entire estate.