I was earlier PM you regarding lost of junction view after updated map. In my 255W now is loaded with 2 maps:
1) City Navigator Singapore/Malaysia NT2011.20 (CN SGM NT 2011.20 ALL)
2) Malsingmaps Malaysia/Singapore/Brunei NT 2011.30 (MSM)
I could be getting a bit lost again, so please help me to look into the below files. I am not sure whether I have the same version in my 255W. The 1st image is GARMIN folder, 2nd is JCV folder.
what i noticed is that you have to rename your cn gmapsupp.img to gmapprom.img (gmapprom reserved for cn map in localized device) & update your cn jvc << get it here >>
as for your malsing map (gmapprom1 reserved for malsing map in localized device), should be ok.
restart your device & check again.
btw gmapsupp.img can be used for other country/region map or placing map in your sd card\Garmin folder.