My sketch of a script for automatic migration is: 1. Check

/proc/cmdline

for

postupdate

, indicating that this is the first boot of a new firmware version. Exit successfully if this is not present. 2. Check for a "breadcrumb" file that marks that the migration has already happened. Exit successfully if this exists. 3. Scan

/etc/network/interfaces

to see if any (non-comment) items mention

eth0

. If not, create the breadcrumb and exit successfully as migration is not required. 4. At this point, the migration needs to be performed. Check if it can be done safely:

/etc/network/interfaces

must NOT mention

br0

and MUST contain exactly one

auto eth0

and

iface eth0 ...

stanza. There must be no other mentions of

eth0

outside of these two lines. If any of these conditions are not met, trigger a reboot to rollback the upgrade. 5. Perform the migration:

s/eth0/br0/

and insert the

bridge-ports node1 node2 node3 node4 ge0 ge1

line under the

iface br0

stanza. Save the old file as

/etc/network/interfaces.old

, put the new file in

/etc/network/interfaces

, create the breadcrumb, and exit successfully.