Lo & Behold: It Just Works (with the Right Adapter…)
A while back, I bought a 4K monitor and set it up with a tower workstation because I had no luck getting it going with my main laptop, a ThinkPad T530.
I was not optimistic about the odds of getting the 4K monitor working with this laptop at all, especially not without the proprietary drivers. But, I had noticed some discussion about an “active” Mini DisplayPort to HDMI adapter working where others hadn’t. I had to pick a few things up at MicroCenter today, and managed to find one such adapter that was about $25. (The rest were about $10.)
Logged out of the desktop, unplugged the Cinema Display, and plugged in the 4K display. And, to borrow a phrase, “it just worked.”
Nice. Very, very nice. The adapter brand is Accell, by the way, if anybody else is looking to get a similar setup going.