An easy way to go back to old firmwares: Load WebUpdater_231.exe from [Only registered and activated users can see links. ]. Install it and drag the old firmware in the same folder. Start webupdater.exe, it ask to update to a newer version, click No !!! and it will install the old firmware to the Nüvi without connecting to the internet. I've tried it several times with my Nüvi 1255T.