OK, seems that the font problem might be caused by wdialog. Kill it since only one or two apps in the pack seem to use it (but they can work without it). Sorry for the inconvenience. Unfortunately I can't test on the real h/w (MSTE) but it wasn't reproducable on either Hatari or STEEM TOS 2.06.
Anyway, I'll be adding GDOS on the pack as well so you could even use different fonts. And I guess I will also need to add a boot manager.
Thanks for your help ggn.