diff --git a/meta-google/recipes-google/ncsi/files/gbmc-ncsi-br-deprecated-ips.sh.in b/meta-google/recipes-google/ncsi/files/gbmc-ncsi-br-deprecated-ips.sh.in
index d6bc9eb..a1b16ca 100644
--- a/meta-google/recipes-google/ncsi/files/gbmc-ncsi-br-deprecated-ips.sh.in
+++ b/meta-google/recipes-google/ncsi/files/gbmc-ncsi-br-deprecated-ips.sh.in
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-[ -z "${gbmc_ncsi_br_deprecated_ips_lib-}" ] || return
+[ -n "${gbmc_ncsi_br_deprecated_ips_lib-}" ] && return
 
 source /usr/share/network/lib.sh || exit
 
@@ -20,41 +20,12 @@
 gbmc_ncsi_br_deprecated_ips_confip=
 gbmc_ncsi_br_deprecated_ips_lastip=
 
-gbmc_ncsi_br_deprecated_ips_addr_contents() {
-  local addr="$1"
-
-  # If our address is assigned explicitly, don't mark it deprecated
-  local line
-  for line in $(grep '^Address=' /etc/systemd/network/*-bmc-@NCSI_IF@.network); do
-    # Remove `Address=` on the input line
-    local apfx="$(echo "$line" | sed 's,^[^=]*=,,')"
-    # ip_pfx_concat is used to normalize the address string for comparison
-    [[ "$addr/128" == "$(ip_pfx_concat "$apfx" ::)" ]] && return
-  done
-
-  cat <<EOF
-[Address]
-Address=$addr/128
-PreferredLifetime=0
-EOF
-}
-
-gbmc_ncsi_br_deprecated_ips_host_contents() {
-  local addr="$1"
-
-  cat <<EOF
-[Network]
-IPv6ProxyNDP=yes
-IPv6ProxyNDPAddress=$addr
-EOF
-}
-
 gbmc_ncsi_br_deprecated_ips_update() {
   [ -n "$gbmc_ncsi_br_deprecated_ips_init" ] || return
   [ "$gbmc_ncsi_br_deprecated_ips_confip" != "$gbmc_ncsi_br_deprecated_ips_lastip" ] || return
   gbmc_ncsi_br_deprecated_ips_confip="$gbmc_ncsi_br_deprecated_ips_lastip"
 
-  printf 'gBMC Bridge NCSI Deprecated Addrs: %s\n' \
+  printf 'gBMC NCSI Deprecated Addrs: %s\n' \
     "${gbmc_ncsi_br_deprecated_ips_lastip:-(deleted)}" >&2
 
   local contents=
@@ -66,21 +37,29 @@
     local pfx="$(ip_bytes_to_str pfx_bytes)"
     (( pfx_bytes[9] &= 0xf0 ))
     local stateless_pfx="$(ip_bytes_to_str pfx_bytes)"
-    local gbmcbr_mac="$(ip link show gbmcbr | tail -n 1 | awk '{print $2}')"
-    local gbmcbr_eui48="$(mac_to_eui48 "$gbmcbr_mac")"
-    local stateless_ip="$(ip_pfx_concat "$stateless_pfx/80" "$gbmcbr_eui48")"
-    stateless_ip="${stateless_ip%/*}"
+    local stateless_ip=
+    if [ -e /sys/class/net/gbmcbr ]; then
+      local gbmcbr_mac="$(ip link show gbmcbr | tail -n 1 | awk '{print $2}')"
+      local gbmcbr_eui48="$(mac_to_eui48 "$gbmcbr_mac")"
+      stateless_ip="$(ip_pfx_concat "$stateless_pfx/80" "$gbmcbr_eui48")"
+      stateless_ip="${stateless_ip%/*}"
+    fi
     pfx_bytes[8]=0
     pfx_bytes[9]=0
     local host_pfx="$(ip_bytes_to_str pfx_bytes)"
-    contents+="$(gbmc_ncsi_br_deprecated_ips_addr_contents "$pfx")"$'\n'
-    contents+="$(gbmc_ncsi_br_deprecated_ips_addr_contents "$stateless_pfx")"$'\n'
-    contents+="$(gbmc_ncsi_br_deprecated_ips_addr_contents "$stateless_ip")"$'\n'
-    contents+="$(gbmc_ncsi_br_deprecated_ips_host_contents "$host_pfx")"$'\n'
+    read -r -d '' contents <<EOF
+[Network]
+IPv6ProxyNDP=yes
+IPv6ProxyNDPAddress=$pfx
+IPv6ProxyNDPAddress=$stateless_pfx
+IPv6ProxyNDPAddress=$host_pfx
+${stateless_ip:+IPv6ProxyNDPAddress=}$stateless_ip
+EOF
     read -r -d '' nfcontents <<EOF
 table inet filter {
   chain ncsi_input {
     ip6 saddr != $pfx/76 ip6 daddr $pfx/76 goto ncsi_gbmc_br_pub_input
+    ip6 daddr $host_pfx/64 goto ncsi_legacy_input
   }
   chain ncsi_forward {
     ip6 saddr != $pfx/76 ip6 daddr $pfx/76 accept
@@ -123,8 +102,9 @@
     gbmc_ip_monitor_defer
   elif [ "$change" = 'defer' ]; then
     gbmc_ncsi_br_deprecated_ips_update
-  elif [ "$change" = 'addr' -a "$intf" = 'gbmcbr' ] &&
-     [ "$scope" = 'global' -a "$fam" = 'inet6' ]; then
+  elif [ "$change" = 'addr' -a "$scope" = 'global' -a "$fam" = 'inet6' ] &&
+      [ "$intf" = 'gbmcbr' -o "$intf" = '@NCSI_IF@' ] &&
+      [[ "$flags" != *deprecated* ]]; then
     local pfx_bytes=()
     ip_to_bytes pfx_bytes "$ip" || return
     # No ULA Addresses