My Edge 530 has a character display problem. Any free, non-commercial OSM based map are not shown at all on 530, just because it was prepared using UTF-8. It is not shown in the list of maps on Edge 530 at all as if it were not on the device in an .img format. So I can call it as a missing map. So one cannot see Central Eastern European characters included in UTF-8.
Later I have heard that the first phenomenon may be the result of a bug coming from a battle of Garmin against pirates (my source: https://openmtbmap.org/garmin/unicode-maps/#gsc.tab=0),
Since UTF-8 is a dead-end street for displaying CEE characters the same map was prepared with Windows-1250 (Central and Eastern European charset) to my request (note: this map covers the CEE region,) BUT all the labels/texts are shown as white ??????? with black rhombuses as their background. So practically the map is useless.
I have no idea why Garmin decided that Edge 530 should not display characters of 1250. Or what sort of other bug / sw glitch /restriction causes it.
Any idea how to make Edge display properly CEE letters like ű and ő of a third party map ???? Why just 1252/Latin works????