GRUB and encrypted /boot

[Volker Wysk]

Hi.

Is it true, that GRUB can nowadays handle fully encrypted mass storage,
which includes the /boot partition? And that this can be set up with the
Ubuntu Server Installer?

ChatGPT told me that, and I browsed around a bit, which seemed to conferm
it.

The thing is, I want Btrfs, which provides the snapshot feature. This is
really cool, but won't work when /boot is in a partition separate from /. 

I've set up the partitions with the Ubuntu Server Installer, several times,
tried Ubuntu Server 24.04 and 25.10, and I think I did it right. But later
in the process I get this message (translated back from German):

"Sorry, a problem occured when finishing the installation." (very
meaningful...)

In the log, this appears:

"grub-install: error: attempt to install to encrypted disk without
cryptodisk enabled. Set 'GRUB_ENABLE_CRYPTODISK=y' in file
'/etc/default/grub'."

Are there any chances to make this work?

TIA,
Volker