these 5 derivations will be built:
  /nix/store/1dypydbcj1izdlwjni4mgyca70pkd8v9-efi-directory.drv
  /nix/store/5m6l5yiilpqh9rv7hfpaby3g8qzp3bj3-efi-image_eltorito.drv
  /nix/store/7wljsw97sfg38pn4wnrqxph5bxi4vh99-isolinux.cfg.drv
  /nix/store/r0mwpp3s6a8v71s6ba3b0l5qipviwvi1-closure-info.drv
  /nix/store/pkwh0xczahxz58z2la6zc4barz0s5fyh-spaces-os.iso.drv
building '/nix/store/7wljsw97sfg38pn4wnrqxph5bxi4vh99-isolinux.cfg.drv'
building '/nix/store/r0mwpp3s6a8v71s6ba3b0l5qipviwvi1-closure-info.drv'
building '/nix/store/1dypydbcj1izdlwjni4mgyca70pkd8v9-efi-directory.drv'
closure-info> tribuchet: building on gi-build-x86-02
isolinux.cfg> tribuchet: building on gi-build-x86-02
efi-directory> tribuchet: building on gi-build-x86-01
closure-info> structuredAttrs is enabled
efi-directory> Building GRUB with modules:
efi-directory>  - fat
efi-directory>  - iso9660
efi-directory>  - part_gpt
efi-directory>  - part_msdos
efi-directory>  - normal
efi-directory>  - boot
efi-directory>  - linux
efi-directory>  - configfile
efi-directory>  - loopback
efi-directory>  - chain
efi-directory>  - halt
efi-directory>  - efifwsetup
efi-directory>  - efi_gop
efi-directory>  - ls
efi-directory>  - search
efi-directory>  - search_label
efi-directory>  - search_fs_uuid
efi-directory>  - search_fs_file
efi-directory>  - echo
efi-directory>  - serial
efi-directory>  - gfxmenu
efi-directory>  - gfxterm
efi-directory>  - gfxterm_background
efi-directory>  - gfxterm_menu
efi-directory>  - test
efi-directory>  - loadenv
efi-directory>  - all_video
efi-directory>  - videoinfo
efi-directory>  - png
efi-directory> Adding additional modules:
efi-directory>  - efi_uga
efi-directory> '/nix/store/c6zqczb7nhr8754qqkpjchyvkxwnch71-refind-0.14.2/share/refind/refind_x64.efi' -> '/nix/store/jj0299mglpcn45gc2lrbq2xg0nyldm8m-efi-directory/EFI/BOOT/refind_x64.efi'
building '/nix/store/5m6l5yiilpqh9rv7hfpaby3g8qzp3bj3-efi-image_eltorito.drv'
efi-image_eltorito> tribuchet: building on gi-build-x86-02
efi-image_eltorito> Usage size: 2097152
efi-image_eltorito> Image size: 3145728
efi-image_eltorito> mkfs.fat 4.2 (2021-01-31)
efi-image_eltorito> Copying BOOTX64.EFI
efi-image_eltorito> Copying grub.cfg
efi-image_eltorito> Copying refind_x64.efi
efi-image_eltorito> fsck.fat 4.2 (2021-01-31)
efi-image_eltorito> Checking we can access the last sector of the filesystem
efi-image_eltorito> Boot sector contents:
efi-image_eltorito> System ID "mkfs.fat"
efi-image_eltorito> Media byte 0xf8 (hard disk)
efi-image_eltorito>        512 bytes per logical sector
efi-image_eltorito>       2048 bytes per cluster
efi-image_eltorito>          1 reserved sector
efi-image_eltorito> First FAT starts at byte 512 (sector 1)
efi-image_eltorito>          2 FATs, 12 bit entries
efi-image_eltorito>       2560 bytes per FAT (= 5 sectors)
efi-image_eltorito> Root directory starts at byte 5632 (sector 11)
efi-image_eltorito>        512 root directory entries
efi-image_eltorito> Data area starts at byte 22016 (sector 43)
efi-image_eltorito>       1525 data clusters (3123200 bytes)
efi-image_eltorito> 32 sectors/track, 2 heads
efi-image_eltorito>          0 hidden sectors
efi-image_eltorito>       6144 sectors total
efi-image_eltorito> Checking for unused clusters.
efi-image_eltorito> /nix/store/cbh0sfmf57gn9crh25p37fs8bg3a2hbm-efi-image_eltorito: 6 files, 719/1525 clusters
building '/nix/store/pkwh0xczahxz58z2la6zc4barz0s5fyh-spaces-os.iso.drv'
spaces-os.iso> tribuchet: building on gi-build-x86-01
spaces-os.iso> structuredAttrs is enabled
spaces-os.iso> Parallel mksquashfs: Using 32 processors
spaces-os.iso> Creating 4.0 filesystem on nix-store.squashfs, block size 1048576.