Venom1802

Hi Everyone I recently bought a Garmin Vista Hcx a couple of weeks ago and after connecting to my PC I ran the updater and updated all the software. My unit is now showing as having Software Version 3.20 and GPS SW Version 2.90. Since doing the update I have noticed strange things like the compass seems to indicate the wrong direction and when moving the triangle marker on the map seems to be travelling sideways in the right direction but pointing the wrong way. I think I'd like to try some earlier software if someone would be kind enough to point me in the right direction. Regards John