mv: failed to preserve ownership ... Operation not permitted
The script was definitely run with sudo.
Error just after ==> Writing bootloader and cleaning up after install...
Log: https://gist.github.com/mxmilkb/c807112897ee6d39ec07007e5154bab9
6:22:38 milk@rose:/run/media/milk/BOOT % ll
total 54M
drwxr-xr-x 15 milk milk 4.0K Dec 16 06:00 dtbs
-rw-r--r-- 1 milk milk 4.7K Dec 16 06:11 boot.ini
-rw-r--r-- 1 milk milk 28M Dec 13 14:37 Image
-rw-r--r-- 1 milk milk 11M Dec 13 14:37 Image.gz
-rw-r--r-- 1 milk milk 7.1M Dec 16 06:09 initramfs-linux.img
-rw-r--r-- 1 milk milk 7.1M Dec 16 06:09 initramfs-linux.uimg
-rw-r--r-- 1 milk milk 397 Sep 15 01:35 sd_fusing.sh
-rw-r--r-- 1 milk milk 835K Sep 15 01:35 u-boot.bin