  We investigate a well studied system of a quantum dot coupled to a Coulomb
box and leads, realizing a spin-flavor Kondo model. It exhibits a recently
discovered non-Fermi liquid (NFL) behavior with emergent SO(5) symmetry. Here,
through a detailed bosonization and refermionization solution, we push forward
our previous work and provide a consistent and complete description of the
various exotic properties and phase diagram. A unique NFL phase emerges from
the presence of an uncoupled Majorana fermion from the flavor sector, whereas
FL-like susceptibilities result from the gapping out of a pair of Majroana
fermions from the spin and flavor sectors. Other properties, such as a
$T^{3/2}$ scaling of the conductance, stability under channel or spin symmetry
breaking and a re-appearance of NFL behavior upon breaking the particle-hole
symmetry, are all accounted for by a renormalization group treatment of the
refermionized Majorana model.
