64st root folder deleted/formatted any options before sent off for warranty?

hello,,
any info or help would be greatly appreciated as the root folder is now completely deleted.
I tried to install ibycus topo but it don't seem to want to read under the "map selection" option on the unit, when I do enter the screen goes blank, I push enter again and it resets the unit. the whole entire folder was wiped clean, and I never planned on this so a backup wasn't made.
if I could get ibycus topo working, my guess would be the required files needed from root folder, but searching everywhere for them or for info, but no luck, my unit came preloaded with Canada topo, but the other files besides the map files are what needed is my guess, even the the language file says missing.
thank you for any help in advance..