I have a number of maps generated from OSM. They have worked perfectly on eTrex 35 and 35T.
Bought two cards - 16GB and 32GB. They work fine in the eTrex. They work fine with Mapinstall. They work fine for normal file transfers.
The maps are clearly visible and usable under Map install. They are clearly visible sa .img files on the PC. They work fine on the eTrex.
On not one of the cards, can I see any maps on the the 66i.
Why?