I created a usb image with live-debian tool and I get the same error. Seems the error is on apt-get command on line 33 of apt-install command. apt-get return 100
in-target sh -c "debconf-apt-progress --no-progress --logstderr -- apt-get -q -y --no-remove install $packages" || ERRCODE=$? Seems grub packages are not on /target/var/cache/apt/archives directory. I copied grub packages to archives directory and regenerated /target/var/cache/apt/pkgcache.bin file by hand using in-target command, but no success. I grep pkgcache.bin. It only found grub package and not grub-pc package. I don't know if this is correct or no. Bye
