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I've created a gentoo-live system which should be booted from a CF-card. The whole file-system is in a squashfs. I've created a custom initrd which first mounts the CF-card and from there the squashed filesystem into what will become /.

I'd like /etc to be writable so I've copied it to the CF-card added a bind. This however does not seem to work. The system boots but /etc is not mounted.

I'd like to know if my approach is right and what I can do to fix it or if not what would be the right way to achieve this.

Here's the init-script from my initrd:

#!/bin/busybox sh
mount -t proc none /proc
mount -t sysfs none /sys

mount /dev/sda1 /mnt/flash
mount -o loop /mnt/flash/filesystem.squashfs /mnt/root
mount -B /mnt/flash/etc /mnt/root/etc
mount -o remount,rw /mnt/root/etc

umount /proc
umount /sys

exec switch_root /mnt/root /sbin/init

This is the shortened output of cat /proc/mounts:

rootfs / rootfs rw 0 0
/dev/sda1 /mnt/flash ext2 rw,relatime,errors=continue,user_xattr,acl 0 0
/dev/loop0 / squashfs ro,relatime 0 0
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Just to be clear, you want changes to /etc to be stored on the CF card to persist across boots? Is the /etc dir from the card not mounted at all (what's the output of cat /proc/mounts?), or only read-only? – depquid Mar 19 '13 at 15:48
You got it right. I want the changes to /etc persisted. It seems /etc is not mounted at all. – Anonymous Coward Mar 19 '13 at 16:04
up vote 2 down vote accepted

BusyBox's built-in mount command doesn't recognize -B; you'll have to use -o bind:

mount -o bind /mnt/flash/etc /mnt/root/etc

Also, I think the remounting is unnecessary if /mnt/flash is already writable. But try fixing the bind mounting first.

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