I've got a pi 3b that boots from the ssd card, but has an external usb drive to store media files. The external drive seems to have died (makes terrible sounds and doesn't spin up) but the bigger problem is that I can't access the system anymore. While booting it times out after waiting for the bad device, then reports "You are in emergency mode." After a few more messages it says
Cannot open access to console, the root account is locked. See sulogin(8) man page fore more details. Press Enter to continue.
But pressing enter or switching to other virtual consoles doesn't give me a command or login prompt. I tried booting in safemode by adding
/boot/cmdline.txt but there's no change.