For anyone running a bootloader there is already an easily available app on XDA which bypasses SafetyNet.
Instead of installing a custom ROM I simply enable developer mode so I could fix the KitKat Bluetooth bug on my LG. SafetyNet detects just having the developer option menu visible, even if turned off, as a violation. The only way I can fix this is through a factory reset (since my LG doesn't give other options to remove developer mode), which was the option I was trying to avoid by enabling developer mode in the first place.
So now, if I want to play Pokemon Go I'll have to do a factory reset on my phone every 2-3 months when the Bluetooth log maxes out.