I recently updated the software on this unit to version 1.840. Since then if I go into water about 6 feet or less or water that has quite a bit of grass, the unit looses the botom signal and starts giving false bottom reading like 950, 1,000, 850 feet or whatever but nowhere close to correct. I've had this happen before sporaticaly on my Solix 12 and even my old Lorwance graphs but it is seldom and once I get in deeper water it straightns itself out and finds the correct depth. The Helix 9 does not fix itself once I'm in deeper water. I have to reboot the graph and then it will work until I get back in shallow water and then it happens again. It ALWAYS does this not occasionally. Lasy trip (yesterday) I finally just turned the unit off.

Any suggestions?

Unfortunately it's a known issue, gonna have to wait for another software update that solves the issue. My Solix didn't have this issue till the current update. I now have the same problem at times

Well that sucks! They have a known problem and it has not been fixed since the software release on 9/20/18 going on four months ago?!!. Shame on Humminbird. They should have released a fix shortly after the problem was identifed since it pretty much makes their graph usless for anyone fishing less than 10 feet of water and with spring spawn getting closer that will be most users.

The latest update was supposed to fix the issue. Obviously it didn't as it has had mixed results since it was released. Some it fixed, some it didn't, and some it created the issue