Firmware flex 205 update x

Will Flexy Firmware update trash my tags and basic program

No, normal firmware updates will not affect your device’s configuration. If you want to be absolutely certain, you can export your Basic script from File → Export in the Basic IDE and you can download your tag list from Diagnostic → Files Transfer under the filename var_lst.csv.

You can also save a normal backup with eBuddy to restore if you ever lose your configuration.