Not sure if ya got the unit similar to mine but sounds like ya did not get Navionics chip and mine is Hook 2-5 Tripleshot preloaded with base maps and came with one year subscription for Navionics updates.Love my unit,screen a tad small but was what I wanted as my flatboat is not that big,16 by 52 and I actually had to send my unit back as it was not reading depths and $230.99 later,got new unit and LOVE it!!Lotta folks have units that accept the mapping cards put out by Standard and mine does not and not an issue as I always have I-Phone with me and GPS is extremely accurate.Use her for duck hunting trips and been tinkering with sidescan and down scan.Definitely a learning curve and buddy of mine turned me onto excellent You Tube Channel,Fish the Moment.This young fellow an expert at electronics-check out his channel,might learn some neat tricks to decoding your unit!!
Mandevillian