Check your HR zones if you had set them manually. They will probably have defaulted back to %MaxHR where the Max HR is set by the age formula.
These settings aren't backed up.
Thanks for the info, I had not realized this and was at first really happy with a very high MaxHR and high VO2Max. I thought my FR955 was trying to make up for all the grief its software developers (or rather their managers) had caused me by flattering me. It certainly brightened my mood - for a short while.
Were there no saved locations in a backup? My backup was empty, but I happened to have file backups of my device so I could restore Lctions.fit. For in the future (who knows what may happen..) it is absolutely worth to copy /Garmin/Settings and Locations to a computer.
I had been using Garmin Explore. All my saved locations in Explore somehow have gotten 3 to 5 copies as a result of the bootloopfest. I'll be removing and reinstalling Explore as I can't make any sense of it anymore.