Strange Problem with /etc/network/interfaces

[Steven Graham]

Hi

I've recently started playing around with busybox and buildroot and
embedded linux in general. Based on a VIA Nano based  mini-itx board I
have a buildroot based setup running on a Compact Flash card, but I've
hit a snag.

I want to setup eth0 so it's automatically brought up.

I know the hardware works as I can do this:

udhcpc eth0

and it gets an ip address and I can ping to both ip addresses and domain
names.

The problem I'm having is with the /etc/network/interfaces file.

As after being built by buildroot, it is:

# Configure Loopback
auto lo
iface lo inet loopback


now I want to change it to this:

auto lo eth0
allow-hotplug eth0
iface lo inet loopback
iface eth0 inet dhcp

The problem I'm having is that no matter how and when I change the file,
it's always read by the target as the first version above. I've tried to
modify it on the target machine, I've also try to modify it on the
development machine. If I modify it on the dev machine and boot up the
target, it still is read as the first version, even if I look at it with
nano. If I put it back in the dev machine, I get the modified version.
If I read it on another machine, I get the modified version as well, but
the target always reads it as the original version.

File modifications on the dev machine are always done with the target
powered down, and before pulling the CF card out of the dev machine I
always make sure it's dismounted first.

What am I doing wrong?

Thanks
Steven Graham