[TechniSol]

It couldn't hurt... Flightcheck is the verification feature in Sigil.

I know you mentioned latest firmware, but what version number is it?

Have you tried epubs and had the same problem? There are two different renderers for epub and kepub...

Have you tried signing out and back in to rebuild the database? You mentioned resets, but not that... Have you noticed any pattern or actions preceding the "crashes"? How long have you waited on a freeze before resetting or powering off? Is it possible if left for a bit longer it unfreezes, or is it a complete crash of the renderer or failure of the Touch input?

I'm just spitballing...