MORE TEST RESULTS
  1. I have been completely unsuccessful in creating a bootable external drive on a Thunderbolt drive
  2. I have been successful in creating a bootable external SSDs on two external drives with USB 3.1 gen 2 connections to Tunderbolt 3 ports
  3. I have been successful in creating a bootable external SSDs on two external drives with USB 3.1 gen 2 connections to USB 3.0 ports
  4. I have been successful in creating a bootable external SSDs on two external drives with USB 3.1 gen 2 connections to USB 3.1 gen 2 ports
  5. My Samsung Thunderbolt 3 SSD refuses to mount on any USB port
  6. I have not attempted to create a bootable drive on rotating rust (HD) media
  7. All attempts used a bootable flash drive installer created using these instructions from OS X Daily


CONCLUSIONS
  1. With the right media and connection it is not difficult to create a bootable external drive for M1 macs given the right combination of connecting media, drive media, and installer
  2. Contrary to other reports I was completely unsuccessful using the Thunderbolt ports to create the drive
  3. The failure of the Samsung X5 SSD to mount is curious given Thunderbolt's compatibility with USB 2.0 through 4. I have to explore this further.


TBD
  • Will an external drive survive having a revised data volume cloned to it via CCC?



Make intentional errors โ€”
Otherwise the Great Spirit realizes you have fulfilled your purpose on earth.

โ€” Navajo saying