How do I change the gcc-arm-none-eabi version through homebrew back to the 2017 q4 release on macOS

The latest formula upgraded the release of gcc-arm-none-eabi to the GCC 7 2018 q2 update. Is there a fairly simple way to roll this back to the 2017 q4 release through homebrew?

I can no longer build stable on the 2018 q2 release, only master.

looks like

brew unlink gcc-arm-none-eabi
brew install gcc-arm-none-eabi-74

should fix the problem.