Can't boot from encrypted disk after attaching/detaching from another machine

Hi all

I connected my laptop's encrypted HDD to my desktop machine to copy some
stuff and when I put it back on the laptop the boot loader no longer
asks for the passphrase and thus I can't boot from it. Any clues? Some
notes:

- Both machines are amd64 running snapshots, 6.2 #115 (Sep 27) on the
laptop, 6.1 #125 (Oct 1) on the desktop (I had to disable pcppi on the
desktop, so not exactly vanilla).

- The softraid volume was and still is correctly attached/detached on
the desktop and on a i386 machine running 6.1-release+mtier

- The metadata changed when connecting to the desktop, roaming from sd1
to sd3. I attached/detached it on the i386 machine to make it roam
back to sd1, just in case, but it expectedly made no difference.

- I ran installboot on the softraid volume, to no avail.

- Tried booting bsd.rd from a USB stick, starting an upgrade, dropping
to shell, MAKEDEV sd0 sd1 sd2, attaching the crypto volume and
selecting it as the root disk. The installer complains that it is not
a valid root disk even though all tests mention here[1] pass:

[1] https://marc.info/?l=openbsd-bugs&m=150170071321416&w=2

Any hints? Thanks in advance
Zé

--