I just spent some time searching around for a solution and finally found something that worked! I’m not using Firebase, but the discussion here was able to help: https://github.com/invertase/react-native-firebase/issues/414 You have to add two lines to your Podfile.
# Add these to your Podfile
pod 'React', :path => '../node_modules/react-native'
pod 'yoga', :path => '../node_modules/react-native/ReactCommon/yoga'
Then run the following to make sure you reinstall your CocoaPods.
cd ios
rm -rf Pods
pod install