  We study the magnetization dynamics in
ferromagnet$\mid$insulator$\mid$ferromagnet and
ferromagnet$\mid$insulator$\mid$normal metal ultra-small tunnel junctions, and
the associated voltage drop in the presence of an electromagnetic environment
assisting the tunneling processes. We show that the environment strongly
affects the resulting voltage, which becomes a highly non-linear function of
the precession cone angle $\theta$. We find that voltages comparable to the
driving frequency $\omega$ can be reached even for small precession cone angles
$\theta$, in stark contrast to the case where the environment is absent. Such
an effect could be useful for the detection local magnetization precessions in
textured ferromagnets or, conversely, for probing the environment via the
magnetization dynamics.
