Actually my previous statement was wrong. It happens sometimes when switching the CT60 form 060 to 030 mode. Next boot, freemint gets lost and somehow persists on using the default binary (mint.prg) despite the presence of a 060 binary (mint060.prg). No big deal, I wouldn't be surprised if the "feature" originates from some CT60-oddity.
When talking about oddities, does anyone observe this (on CT60): I boot into freemint (might be just pure basic shell, nothing special), then I do software reset ('reboot' or from xaaes) into TOS and there's 90% chance I get sooner or later bus error. When I use hardware reset or reset from that bus error state, TOS is sound and stable. I have no clue what could cause it, certainly it's something in kernel/ct60tos, not some external app.