diff --git a/sdk_container/src/third_party/coreos-overlay/coreos/config/make.conf.amd64-target b/sdk_container/src/third_party/coreos-overlay/coreos/config/make.conf.amd64-target
index 8de75eb292..4b64c069c6 100644
--- a/sdk_container/src/third_party/coreos-overlay/coreos/config/make.conf.amd64-target
+++ b/sdk_container/src/third_party/coreos-overlay/coreos/config/make.conf.amd64-target
@@ -8,12 +8,5 @@ source make.conf.board_setup
 # Common settings across all board targets.
 source make.conf.common
 
-# Recommended MARCH_TUNE, CFLAGS, etc.
-MARCH_TUNE=""
-
-# Allow a board to override or define additional settings.
-CFLAGS="-O2 -pipe ${MARCH_TUNE} -g"
-CXXFLAGS="${CFLAGS}"
-
 # Allow the user to override or define additional settings.
 source make.conf.user
diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/amd64/generic/make.defaults b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/amd64/generic/make.defaults
new file mode 100644
index 0000000000..254f8753a5
--- /dev/null
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/amd64/generic/make.defaults
@@ -0,0 +1,3 @@
+# Enable optimizations for common x86_64 CPUs
+CFLAGS="-O2 -pipe -mtune=generic"
+CXXFLAGS="${CFLAGS}"
diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/amd64/sdk/make.defaults b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/amd64/sdk/make.defaults
new file mode 100644
index 0000000000..254f8753a5
--- /dev/null
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/amd64/sdk/make.defaults
@@ -0,0 +1,3 @@
+# Enable optimizations for common x86_64 CPUs
+CFLAGS="-O2 -pipe -mtune=generic"
+CXXFLAGS="${CFLAGS}"
diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/generic/make.defaults b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/generic/make.defaults
index a6977e0323..84929f64cd 100644
--- a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/generic/make.defaults
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/generic/make.defaults
@@ -3,7 +3,7 @@
 
 USE="cros-debug acpi usb symlink-usr -pam"
 USE="${USE} -cros_host -expat -pic -pie -cairo -X"
-USE="${USE} -acl -cracklib -gpm -ipv6 -openmp -python -sha512"
+USE="${USE} -acl -cracklib -gpm -openmp -python -sha512"
 USE="${USE} -fortran -abiword -perl -cups -poppler-data -nls"
 
 # Exclude documentation
diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/generic/package.use b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/generic/package.use
index 64cce95d85..2738000830 100644
--- a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/generic/package.use
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/targets/generic/package.use
@@ -12,14 +12,11 @@ dev-python/pyudev	pygobject
 dev-util/perf		-doc -demangle -tui -ncurses -perl -python
 dev-util/perf-next	-doc -demangle -tui -ncurses -perl -python
 net-analyzer/tcpdump	-chroot
-net-firewall/iptables	ipv6
-net-misc/dhcp		ipv6 -server
+net-misc/dhcp	        -server
 net-misc/iperf		threads
-net-misc/iputils	ipv6
 net-misc/ntp            caps
 sys-apps/busybox	-pam -selinux
 sys-apps/dbus		-X -systemd
-sys-apps/iproute2	ipv6
 sys-apps/smartmontools	minimal
 sys-block/parted        device-mapper
 sys-fs/lvm2		-lvm1 -readline -static