  Recently we showed how non-homogeneous second-order difference equations
appearing within ABJM quantum spectral curve description could be solved using
Mellin space technique. In particular we provided explicit results for
anomalous dimensions of twist 1 operators in sl(2) sector at arbitrary spin
values up to four loop order. It was shown that the obtained results may be
expressed in terms of harmonic sums decorated by fourth root of unity factors,
so that maximum transcendentality principle holds. In this note we show that
the same result could be also obtained by direct solution of the mentioned
equations in spectral parameter u-space. The solution involves new highly
nontrivial identities between hypergeometric functions, which may have various
other applications. We expect this method to be more easily generalizable to
higher loop orders as well as to other theories, such as N=4 SYM.
