I had that issue and what you need to do is either fully restore ChromeOS by burning a restore USB stick (Mac/windows follow these steps: https://support.google

I had that issue and what you need to do is either fully restore ChromeOS by burning a restore USB stick (Mac/windows follow these steps: https://support.google.com/chromebook/answer/1080595?hl=en https://support.google.com/chromebook/answer/1080595?hl=en or on Linux can run this script: https://dl.google.com/dl/edgedl/chromeos/recovery/linux_recovery.sh https://dl.google.com/dl/edgedl/chromeos/recovery/linux_reco... ). Then once you have chrome os back you can get it in developer mode, unlock the firmware, etc (mrchromebox has instructions). Alternatively you can use gallium OS' fix flags USB recovery stick as an alternative to restoring chrome os: https://galliumos.org/fixflags/README https://galliumos.org/fixflags/README and the images https://galliumos.org/fixflags/ https://galliumos.org/fixflags/ ). This acts like a chrome os restore stick but instead of reinstalling chrome os it flips on the legacy bios bits so you can install a Linux OS and then run mrchromebox's firmware flash. Ultimately you'll need to fix your internal drive though to get something you can install onto first. You might go the official ChromeOS restore stick approach just to get it all back into a known good state, then experiment with blowing away the firmware to replace with coreboot.