No loader.lua boot error after upgrade to 13-STABLE

Hi,

After source upgrading my Thinkpad to 13.0-STABLE at c3915f848b56 it
ends up booting with an error:

ERROR: cannot open /boot/lua/loader.lua: no such file or directory

Yet the same source build runs flawlessly on my desktop with full
disk ZFS setup, the laptop is UFS based though. I have read a bunch of
tickets at bugzilla, including: 233098, 238749, 251250 – and have not
found a solution.

I had used the same steps to upgrade as usual:
* cd /usr/src
* make installkernel installworld DESTDIR=/mnt
* mergemaster -FUia -D /mnt

The affected SSD had been setup with GPT scheme. The laptop drive setup
is as follows: 

* the whole SSD is used for FreeBSD
** p1 boot - offset by 40 blocks and of 472 size
** p2 swap - 4G, encrypted
** p3 root - GELI encrypted UFS aligned to 4k

What am I missing?
-- 
 Piotr Smyrak