Originally Posted by Zetmolm
I'm 99.9% sure that the M92 supports mobi.
As the M92 and the Excel have basically the same firmware it would be very surprising if there is a difference in format support.
Agreed, and it turns out there isn't. I don't know why the specs page doesn't list it, but the M92 manual mentions non-DRMed mobi as a supported format.