steps to reproduce:

• run, through entire quick start
• restart, hit leftAlt+u and see an underscore '_' in the terminal
• run, optimize_boot
• restart, hit leftAlt+u and see nothing
  --- sequence of attempts to resolve
• try, reset cmdline.txt
• restart, hit leftAlt+u and see nothing
• try, reset config.txt
• restart, hit leftAlt+u and see nothing
• try, enable all disabled
• restart, hit leftAlt+u and see an underscore '_' in the terminal
• try, disable keyboard-setup
• restart, hit leftAlt+u and see nothing
• try, run optimize_boot, enable keyboard-setup
• restart, hit leftAlt+u and see an underscore '_' in the terminal