Description:
I am getting the following error while executing
sudo ./build.sh -v

***
[mkarchiso] INFO: Configuration settings
[mkarchiso] INFO: Command: run
[mkarchiso] INFO: Architecture: x86_64
[mkarchiso] INFO: Working directory: work/x86_64
[mkarchiso] INFO: Installation directory: arch
[mkarchiso] INFO: Run command: /root/customize_airootfs.sh

Generating locales...
en_US.UTF-8... done
Generation complete.
Created symlink /etc/systemd/system/multi-user.target.wants/pacman-init.service → /etc/systemd/system/pacman-init.service.
Created symlink /etc/systemd/system/multi-user.target.wants/choose-mirror.service → /etc/systemd/system/choose-mirror.service.
Created symlink /etc/systemd/system/default.target → /usr/lib/systemd/system/multi-user.target.
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 887k 100 887k 0 0 1956k 0 --:--:-- --:--:-- --:--:-- 1955k
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 753k 100 753k 0 0 1636k 0 --:--:-- --:--:-- --:--:-- 1637k
mkfs.fat 4.0 (2016-05-06)
cp: error writing 'work/efiboot/EFI/archiso/intel_ucode.img': No space left on device
***

I am getting this error on different devices, thus I don't think that
this is a space issue specific to the build system.

Also I get the following error while building the image:
***
-> Running build hook: [archiso_shutdown]
-> Running build hook: [archiso]
-> Running build hook: [archiso_loop_mnt]
-> Running build hook: [archiso_pxe_common]
/usr/lib/initcpio/functions: line 373: ${module//-/_}: bad substitution
==> Generating module dependencies
==> Creating xz-compressed initcpio image: /boot/archiso.img
bsdcpio: Failed to set default locale
==> Image generation successful
***


Steps to reproduce:
cp -r /usr/share/archiso/configs/releng ./
cd releng
sudo ./build.sh -v