Responsa for Bava Batra 249:6

מאי סבתא דההוא דאמר להו

may re-collect it from them!<span class="x" onmousemove="('comment',' Although they received that land after the death of their father, it is regarded as having itself been 'in the father's possession, since it had been obtained through the money (debt) bequeathed to them by their father. In the case of the birthright also, since the land was obtained through the debt that was bequeathed by their father, it should be regarded as having been in his possession, and the first-born should take a double portion; how, then, could R. Nahman say that if land was collected for a debt, the firstborn does not receive a double portion? ');">⁵</span> — He replied to him: There is no difficulty according to me, nor is there any difficulty according to R. Nahman. We were stating the reason of the Palestinians,<span class="x" onmousemove="('comment',' Who hold that a firstborn takes a double portion in a loan, and this gave rise to the differences of opinion between Rabbah and R. Nahman. ');">⁶</span> but we ourselves<span class="x" onmousemove="('comment',' Lit., 'and to us'. ');">⁷</span> do not hold [this] opinion.<span class="x" onmousemove="('comment',' But share the opinion of Rab and Samuel that the right of primogeniture does not apply to a loan and the whole question, whether the payment was made in money or land, does not arise. ');">⁸</span> What [was the story of the] grandmother? [Once] a certain [person] said to them:<span class="x" onmousemove="('comment',' His executors. ');">⁹</span>

Teshuvot Maharam