Unfortunately it's not a new issue. Nothing much you can do. If you have a second monitor or are willing to obtain one, you should be able to use that one to display the boot screens, and then your 4K will turn on after booting.
If you want it all (a single 4K @ 60Hz monitor that shows boot screens) your only option is to buy a Maxwell or later card from MacVidCards. Aside from the expense, the biggest downside is needing to install Nvidia Web Drivers every time the OS is updated. And if you have (or will have) any desire to install Mojave, there are as of yet (two months after release) no Nvidia drivers for those cards in Mojave. It's anyone's guess as to whether or not there will ever be.