Ok, so I was flashing Chevy's new Rom onto my phone. It was successful.
I had some crap on there I wanted to get ride of; so, booted into Clockwork Recovery, formated system/data/cache, installed Chevy's rom again, and rebooted.
Hung on M boot screen. Battery pull for same result. Booted into bootloader and plugged it in to sbf. USB Transfer enabled on phone, adb devices shows nothing. This has never happened before, my drivers are up-to-date, etc.
Thought it might just be my computer acting up, so moved from my linux machine to windows. Plugged it in, said driver was installed successfully (also had updated drivers as I originally rooted the phone using adb tools on the windows machine). Adb devices also shows nothing on this machine as well.
Booted into recovery mode and formated data/factory reset. Still hangs on M.
All out of ideas and worried.
Also note that this means that RSD_Lite 4.8 for example will not show any devices listed, making an SBF seemingly impossible. I originally noticed the issue only because I was attempting sbf_flash and it said no devices listed.