Moving raw system image to another drive breaks GELI

[David Christensen]

freebsd-questions:

I have a computer:

2019-02-26 09:50:14 dpchrist at ragnar ~
$ freebsd-version ; uname -a
11.2-RELEASE-p9
FreeBSD ragnar 11.2-RELEASE-p9 FreeBSD 11.2-RELEASE-p9 #0: Tue Feb  5 
15:30:36 UTC 2019 
root at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC  amd64


I installed to a SanDisk Ultra Fit USB 3.0 16 GB flash drive:

       Partitioning                      Auto (ZFS)
         Pool Type/Disks                 stripe,da0
         Pool Name                       zroot
         Force 4K Sectors                YES
         Encrypt Disks                   YES
         Partition Scheme                MBR (BIOS)
         Swap Size                       2g
         Mirror Swap                     NO
         Encrypt Swap                    YES
         Install


If I do a raw binary copy of the USB flash drive to a Intel 520 Series 
SSD 60 GB with dd(1) and boot the SSD, GELI rejects the passphrase and I 
end up at a "mountroot>" prompt.


I would like to be able to move raw FreeBSD system images from drive to 
drive and have them work.


Suggestions?


David