Thanks for your reply.
The map in question is not a raster map. It is coloured isobaths (at5 compatible colours) and the problem is that the colour does not light up until the Simrad NSE 12 is zoomed in to 20 m on the zoomscale. The black depth-curves show up earlier. On a Simrad NSS Evo 2 the map shows colours on 2 km zoom level. On HDS gen 2 units the colours also show up on 2 km zoom level. I think this might be an issue on Simrad NSE 12 only. I will try disabling shaded relief and see if it helps.
Reefmaster has a dedicated IMC output option and raster maps from reefmaster work fine on HDS and the Simrad NSE 12 unit. I am a toolkit partner and try to find a format that work on as many Lowrance models as possible, or at least the current models. It is a problem all HDI-units won't display raster maps properly, and for some reason I can't make the rebind-fix work on my maps.
Another issue I discovered a few days ago is that the Elite HDI 7x won't display the non-raster map mentioned above at all. Simrad, HDS gen 1 and 2, and elite units (non HDI) displays it but the HDI 7X refuses. I have a very basic map with only 4 colours that is created with Atlas 6 that displays on almost every unit with colour-screen that worked fine on the Elite HDI 7x also, but I am sure this unit can do better...
I am not meaning to complain here, just need to find a map format that works on all current/supported Lowrance units. I am happy to email you examples from my maps if that could help.
What would you suggest I try in order to make a map that works for all current models?