Precise Alternate CD comes with netcfg 1.68 (netcfg_1.68ubuntu14_amd64.udeb) and this version of netcfg writes out two iface entries for eth0 when it has dhcp/dhcp6 assigned or SLAAC assigned global IPv6 addresses (write_interface.c).
The ifblacklist_migrate.sh only disables the first entry because of the dhcp tag, and doesn't disable the second, so we end up with an unmanaged NIC according to NetworkManager and no IPv4 address.
Precise Alternate CD comes with netcfg 1.68 (netcfg_ 1.68ubuntu14_ amd64.udeb) and this version of netcfg writes out two iface entries for eth0 when it has dhcp/dhcp6 assigned or SLAAC assigned global IPv6 addresses (write_ interface. c).
The ifblacklist_ migrate. sh only disables the first entry because of the dhcp tag, and doesn't disable the second, so we end up with an unmanaged NIC according to NetworkManager and no IPv4 address.