What a pain lol. I've found the error and resolution in my ways. The new surfaces come with Windows 10 installed and encryption enabled. Well I was imaging windows 8 on it without clearing the encryption first and since there is a separate TPM module, it was recognizing the OS didn't match.
To fix this was a bit more complicated and I can't remember my exact steps.
These were my steps:
- Create a restore point
- Disable/Reenable Secure Boot and TPM
- Use recovery usb to 'reset pc' - gets to 66% or so then fails.
- Get prompted to clear tpm - this bricks it (uefi boot loop)
- Turn off surface
- Hold power and volume down to boot back to usb
- System restore back to the one I created.
- Back to Windows 8 and TPM unlocked.
To fix this going forward, I will clear the tpm and unencrypt the drive first, then reimage. Lesson learned.
Thanks for your help! :)