  We calculate the fermionic corrections to the photon-energy spectrum of Bbar
-> X_sgamma which arise from the self-interference of the chromomagnetic dipole
operator Q_8 at next-to-next-to-leading order by applying naive
non-abelianization. The resulting O(beta_0 alpha_s^2) correction to the Bbar ->
X_sgamma branching ratio amounts to a relative shift of +0.12% (+0.27%) for a
photon-energy cut of 1.6 GeV (1.0 GeV). We also comment on the potential size
of resummation and non-perturbative effects related to Q_8.
