Latest firmware for 53/55/56 HWID 1697 is V5.40. Here is patched SD pack for it. [Only registered and activated users can see links. ] both before and after flashing.
WARNING TO OTHER USERS: This pack is for HWID 1697 nuvi 53/55/56 devices ONLY. Do not modify it for use in other devices unless you know exactly what you're doing as you can very easily HARD-BRICK your device using a wrong BIN or HWID.