Comment # 4 on bug 1124423 from Mindaugas Baranauskas

Created attachment 796094 [details]
"Sudoers dir is not writable." even with source:
"/run/initramfs/live/LiveOS/squashfs.img"

/usr/share/calamares/modules/unpackfs.conf contains:

---
unpack:
    -   source: "/run/initramfs/live/LiveOS/squashfs.img"
        sourcefs: "squashfs"
        destination: "/"