Can't create Nexus 5X image due to "No space left on device"

It seems I'm unable to create an image for the Nexus 5X anymore (other devices, including Qemu, work fine).

In step 4 out of 5 in pmbootstrap install it fails with the following (it had lots more of these lines but you get the point):

cp: can't create directory '/mnt/install/usr/etc': No space left on device
cp: can't create directory '/mnt/install/usr/sbin': No space left on device
cp: can't create directory '/mnt/install/usr/local': No space left on device
cp: can't create directory '/mnt/install/usr/aarch64-alpine-linux-musl': No space left on device
cp: can't create directory '/mnt/install/run': No space left on device
cp: can't create directory '/mnt/install/proc': No space left on device
(019604) [00:57:57] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This happens no matter what UI I use, even with "none".