Feedback for v1.14

Sony
XZ1 Compact
lilac
1.13
Not rooted

I downloaded the update and initiated the install process.

Phone rebooted and started install (I think), but is stuck on a slightly illuminated, dark, blank screen and does not advance.

A press of the power button, which would normally deactivate the screen, does nothing.

It has been in this state for over 20 minutes and counting.

What should I do? Hard power-down? (If that’s possible.)

EDIT:
Power button does not power down phone.

Vol Up+Power until 3 vibrations (indicating soft reset, I think) powers the phone down.

Vol Down+Power (to boot into recovery from the powered off state) returns to the original problem: dark screen (power is on) that won’t advance.

Power on (from powered off state) flashes vendor screen, but then returns to the dark screen (power is on) that won’t advance.

Any suggestions, anyone?

EDIT: See my recovery solution below.