External HDD not bootable after install

  1. Please read this:
    How to provide good information
    and give us more information so we can see what’s really going on.
    Now we know the symptom of the disease, but we need some more probing to know where the origin lies… :grin:
  2. An inxi --admin --verbosity=7 --filter --no-host --width would be the minimum required information for us to be able to help you. (Personally Identifiable Information like serial numbers and MAC addresses will be filtered out by the above command)
    Also, please copy-paste that output in-between 3 backticks ``` at the beginning and end of the code/text.

:+1:

P.S. If you want to notify me that you did provide this information, please :heart: this message and I’ll come back and have another look.
P.P.S. If you enter a bit more details in your profile, we can also see which Desktop Environment you’re using, which exact CPU/GPU or Kernel, … you have without typing it every time