  We compute semi-leptonic $B_s$ decay form factors using Heavy Quark Effective
Theory on the lattice. To obtain good control of the $1/m_b$ expansion, one has
to take into account not only the leading static order but also the terms
arising at $O(1/m_b)$: kinetic, spin and current insertions. We show results
for these terms calculated through the ratio method, using our prior results
for the static order. After combining them with non-perturbative HQET
parameters they can be continuum-extrapolated to give the QCD form factor
correct up to $O(1/m_b^2)$ corrections and without $O(\alpha_s(m_b)^n)$
corrections.
