They are, indeed, and there has already been a brief discussion about this issue earlier. The suggestion was even made by one of the Team members to return to ext4
as the default filesystem.
The root of the problem is however neither btrfs
nor calamares
, but the lack of proper btrfs
support in grub
. But only upstream — i.e. the GNU developers — can properly remedy that.
In the meantime, things appear to be a hit-and-miss. For some, there’s no problem at all. For others, there is.
However — and we are looking past the issue here — this problem is supposedly why the 25.0.4 ISOs were pushed out, while the OP is still trying to install from a 25.0.3 ISO.
Addendum:
If the OP does not want to download a more recent ISO, then I would suggest opting for manual partitioning and either creating a separate /boot
partition of about 512 MiB — which is enough to hold a couple of kernels — with an ext4
filesystem, or just choosing ext4
instead of btrfs
all across the board, which is perhaps the easiest solution.