I'm trying to overlay an empty upper dir onto a fat/loop/img fs and getting: juser@negk:~/boot$ sudo mount -o ro /dev/mapper/loop0p1 img juser@negk:~/boot$ sudo mount -t overlay overlay -olowerdir=img,upperdir=upper,workdir=work merged mount: /home/juser/boot/merged: wrong fs type, bad option, bad superblock on overlay, missing codepage or helper program, or other error. [ 2449.670177] overlayfs: filesystem on 'lower' not supported code to replicate: mkdir boot cd boot mkdir img lower upper work merged wget http://downloads.raspberrypi.org/raspios_lite_armhf/images/raspios_lite_armhf-2020-05-28/2020-05-27-raspios-buster-lite-armhf.zip unzip 2020-05-27-raspios-buster-lite-armhf.zip sudo kpartx -av 2020-05-27-raspios-buster-lite-armhf.img sudo mount /dev/mapper/loop0p1 img # this errors: sudo mount -t overlay overlay -olowerdir=img,upperdir=upper,workdir=work merged # this does not cp img/* lower/ sudo mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir=work merged https://github.com/CarlFK/pici/blob/main/test1.sh The goal is to netboot a pi using the files from the .img with a few changes, the root kernel parameter needs to be changed from local storage to nfs: # tftp/cmdline.txt root=/dev/nfs nfsroot=10.21.0.1:/srv/nfs/rpi/root,vers=4.1,proto=tcp rw ip=dhcp rootwait elevator=deadline consoleblank=0 I can copy all the files from the .img into a dir, but I am thinking I should be able to overlay a dir on top to manage the changes. If you want to see my netboot pi server setup https://github.com/CarlFK/pici/blob/main/setup.md -- Carl K
