Upgrade (and 1st reboot) went thru without any problem, but after 2nd reboot system was unable tu start (gptzfsboot: error 32 lba 1).
Downloaded and install 11.1-U6 again (I have got backuped config). Splited mirrored boot device in order to have backuped 11.1-u6 system. Downloaded 11.2 image. I try to prepare installation media, but written by Unetbootin has not booted (Invalid or corrupted kernel image). Rufus (v 3.3 and 3.4) caused BSOD when 99.6% of immage was written. My PC has not started with this pendrive attached. Connecting this pendrive caused immediate BSOD. I was able to repair it only with Gparted under Linux creating a new partition table (Gparted reportet corrupter partition table).
Only Image writer was able to write image to pendrive, but after booting I got just a blinking "\".
It is an HP N54L Microserver with 5x3TiB disks in raidz2.
The simmilar issue I had a few weeks ago, I tried to upgrade to the beta version: