  Using soft-collinear effective theory (SCET), we examine the 1/m_b
corrections to the factorization formulas for inclusive semi-leptonic B decays
in the endpoint region, where the hadronic final state consists of a single
jet. At tree level, we find a new contribution from four-quark operators that
was previously assumed absent. Beyond tree level many sub-leading
shape-functions are needed to correctly describe the decay process.
