Installing bullseye into previously existing encrypted disk with buster

[Nitebirdz <nitebirdz@sacredchaos.com>]

Hi,


I currently have a laptop running buster on an encrypted disk that boots
via EFI. The filesystems look like this: 

/dev/mapper/tangier--vg-root            /
/dev/mapper/tangier--vg-home            /home
/dev/sda1                               /boot/efi
/dev/sda2                               /boot

I know I can easily upgrade to bullseye from the running system. However,
what I usually do when it's time to upgrade Debian on a laptop is to start
from a clean slate. It's my chance to clean up and remove old cruft (well,
with the exception of my own home partition, of course). So, instead of
upgrading, I just install the new version of Debian. 

Now, my problem is that, whenever I launch the installer, it wants to
partition the disk. Is there a way to tell the installer to leave the
existing partitioning scheme alone? Also, I'd need the installer to leave
the home partition alone, and format and install over the other
partitions. Is this possible? If so, how? I've been trying different
approaches, and I don't seem to be able to find the way to do it. 


Thanks. 

-- 
Nitebirdz