follow #1 post D/L 23xx series and 1.Unrar the file in an empty SD card(I use sandisk 1G in my moto v3i which is FAT) then step by step.
start Nuvi 2455, NOTHING Happen!! Just normal start. So, I think maybe the SD card problem, then I reformat it in windows 7 using FAT32 and try again, Still....Nothing Happen!! Am I doing something wrong? Also Check: / .System / diag / html / supported_features.html there is no different at all.