[Trisquel-users] Can't boot after update

[aaron]

I ran a Trisquel update and now my computer, a MacBook A134, won't boot. Can  
someone recommend steps to debug it? I'm not physically at the computer, but  
my 72-year-old father can be guided through not-too-tortuous tasks. The only  
context I can think to add is that the computer previously ran fine but would  
never start up on its own after a reboot. A reboot would always just shut it  
down.