As I am not sure, if this is a bug or a personal mistake, I decided to post it here in the forum.
I don't know how to face the issues below. I would be very thankful if you could help me to solve those.

In order to build packages for armv7h on a x86_64 machine, I followed the guide on the wiki using libretools.

After building several packages I cannot update an existing arm chroot:

$ librechroot -n arm update
...
(2/2) checking available disk space                            [##################################] 100%
error: Partition / is mounted read only
error: not enough free disk space
error: failed to commit transaction (not enough free disk space)
Errors occurred, no packages were upgraded.

I have 280 GB free disk space, so I don't understand why this error arises.

As I wanted to check whether parabolas [libre/qemu-user-static-binfmt] is at the current version I saw that this package is not included in Arch's repository. Probably this package is not up to date in parabola's repo and replaced by another one?

EDIT: Split issue into two separe ones.