I flash Roms fairly often on my Note 3 (mostly for upgrades, or to try to remove weird problems), but I haven't come across a decent way to back up my Gear 2. I just roll with it, and when I get my watch re-paired, I go into Sammy Apps under the Purchased section, and reload my apps through that. It functions like an 'all apps ever installed' list, which saves a little time. I haven't had luck with TiBu or similar services - the phone says the apps will be installed, but they won't be on the watch. Wish I had a better answer for you.