  We comment on the recent work [N. Harrison, \textit{et al.} Phys. Rev. B {\bf
92}, 224505 (2015)] which attempts to explain the sign reversal and quantum
oscillations of the Hall coefficient observed in cuprates from a single nodal
diamond-shaped electron pocket with concave arc segments. Given the importance
of this work, it calls for a closer scrutiny. Their conclusion of sign reversal
of the Hall coefficient depends on a non-generic rounding of the sharp
vertices. Moreover, their demonstration of quantum oscillation in the Hall
coefficient from a single pocket is unconvincing. We maintain that at least two
pockets with different scattering rates is necessary to explain the observed
quantum oscillations of the Hall coefficient.
