Core stuck blinking white/magenta after deep update

Hello -

My Spark/Particle Core (purchased from the original crowdfunding run) functioned great as a beer keg consumption tracker for years. I recently decided to repurpose it but have run into issues. I ran the deep update via the particle cli. Now my Core refuses to go into listening mode. It is either stuck breathing a (bluish) white very quickly, breathing a (bluish) white very slowly, or flashing purple.

I’ve tried flashing the cc3000 update followed by tinker, then factory resetting. I’ve tried numerous combinations of restarting and flashing different firmwares. I’ve somewhat given up and ordered a new Particle, but would love to get my original Core up and working again too. Can someone please help?

Continuing the discussion from Core stuck blinking white/magenta: