Hi!
I have just downloaded Unity Firebase 4.0.0, and when installing a black/console window popped up momentarily trying to get the installed Android packages (I dont remember exactly the contents of that window), but there was an error message saying "android" command is deprecated and explaining alternative ways of doing it.
After a few seconds the window closed and an error popped up on Unity console:
Unable to determine which Android packages are installed. Failed to run /Users/xxx/dev/adt/sdk/tools/android. /Users/xxx/dev/adt/sdk/tools/android: line 115: ${trysdkresponse,,}: bad substitution
(2)
UnityEngine.Debug:LogError(Object)
GooglePlayServices.<GetAvailablePackages>c__AnonStorey7:<>m__F(Result)
GooglePlayServices.ProgressReporter:Update(CommandLineDialog)
GooglePlayServices.CommandLineDialog:Update()
UnityEditor.EditorApplication:Internal_CallUpdateFunctions()
I have no idea now if the installation is corrupted and how to I get back to the old version.
I'm on OSX, I have Android SDK Build-Tools 26 installed, Android SDK Platform Tools 26.0.0, and Android SDK Tools 26.0.2.
Best