diff --git a/build_library/vm_image_util.sh b/build_library/vm_image_util.sh
index 2623ebc044..1cae8d12dd 100644
--- a/build_library/vm_image_util.sh
+++ b/build_library/vm_image_util.sh
@@ -227,20 +227,35 @@ setup_disk_image() {
     if [[ $(_get_vm_opt BOOT_KERNEL) -eq 0 ]]; then
         sudo mv "${SYSLINUX_DIR}/default.cfg.A" "${SYSLINUX_DIR}/default.cfg"
     fi
+
+    # The only filesystem after this point that may be modified is OEM
+    # Note: it would be more logical for disk_util to mount things read-only
+    # to begin with but I'm having trouble making that work reliably.
+    # When mounting w/ ro the automatically allocated loop device will
+    # also be configured as read-only. blockdev --setrw will change that
+    # but io will start throwing errors so that clearly isn't sufficient.
+    local mnt
+    for mnt in $(findmnt -nrR -o target -T "${VM_TMP_ROOT}"); do
+        if [[ "${mnt}" != */usr/share/oem ]]; then
+            sudo mount -o remount,ro "${mnt}"
+        fi
+    done
 }
 
 # If the current type defines a oem package install it to the given fs image.
 install_oem_package() {
     local oem_pkg=$(_get_vm_opt OEM_PACKAGE)
-    local oem_mnt="${VM_TMP_ROOT}/usr/share/oem"
+    local oem_tmp="${VM_TMP_DIR}/oem"
 
     if [[ -z "${oem_pkg}" ]]; then
         return 0
     fi
 
     info "Installing ${oem_pkg} to OEM partition"
-    emerge-${BOARD} --root="${oem_mnt}" --root-deps=rdeps "${oem_pkg}"
-    sudo rm -rf "${oem_mnt}/var"  # clean out /var/pkg/db and friends
+    emerge-${BOARD} --root="${oem_tmp}" \
+        --root-deps=rdeps --usepkg --quiet "${oem_pkg}"
+    sudo rsync -a "${oem_tmp}/usr/share/oem/" "${VM_TMP_ROOT}/usr/share/oem/"
+    sudo rm -rf "${oem_tmp}"
 }
 
 # Write the vm disk image to the target directory in the proper format
diff --git a/build_packages b/build_packages
index 0f408aedb8..a46177677a 100755
--- a/build_packages
+++ b/build_packages
@@ -63,12 +63,6 @@ DEFINE_boolean skip_chroot_upgrade "${FLAGS_FALSE}" \
   "Don't run the chroot upgrade automatically; use with care."
 DEFINE_boolean skip_toolchain_update "${FLAGS_FALSE}" \
   "Don't update toolchain automatically."
-DEFINE_boolean withdev "${FLAGS_TRUE}" \
-  "Build useful developer friendly utilities."
-DEFINE_boolean withdebug "${FLAGS_TRUE}" \
-  "Build debug versions of Chromium-OS-specific packages."
-DEFINE_boolean withtest "${FLAGS_TRUE}" \
-  "Build packages required for testing."
 
 # The --reuse_pkgs_from_local_boards flag tells Portage to share binary
 # packages between boards that are built locally, so that the total time
@@ -186,28 +180,6 @@ if [[ "${FLAGS_showoutput}" -eq "${FLAGS_TRUE}" && \
   EMERGE_FLAGS+=( --show-output )
 fi
 
-if [[ "${FLAGS_withdebug}" -eq "${FLAGS_FALSE}" ]]; then
-  export USE="${USE} -cros-debug"
-fi
-
-# Figure out which packages we should be building.
-PACKAGES=( "$@" )
-if [[ $# -eq 0 ]]; then
-  PACKAGES=( coreos-base/coreos )
-  if [[ "${FLAGS_withdev}" -eq "${FLAGS_TRUE}" ]]; then
-    PACKAGES+=( coreos-base/coreos-dev )
-  fi
-fi
-
-# Verify that all packages can be emerged from scratch, without any
-# backtracking. Only print the output if this step fails.
-info "Checking package dependencies are correct: ${PACKAGES[*]}"
-if ! OUTPUT=$(emerge-${FLAGS_board} -pe --backtrack=0 \
-              "${PACKAGES[@]}" 2>&1); then
-  printf "%s\n" "${OUTPUT}"
-  die_notrace "emerge detected broken ebuilds. See error message above."
-fi
-
 # Build cros_workon packages when they are changed.
 CROS_WORKON_PKGS=()
 if [ "${FLAGS_noworkon}" -eq "${FLAGS_FALSE}" ]; then
@@ -223,7 +195,7 @@ if [[ ${#CROS_WORKON_PKGS[@]} -gt 0 ]]; then
 fi
 
 info "Merging board packages now"
-sudo -E "${EMERGE_CMD[@]}" "${EMERGE_FLAGS[@]}" "${PACKAGES[@]}"
+sudo -E "${EMERGE_CMD[@]}" "${EMERGE_FLAGS[@]}" coreos-devel/board-packages
 
 info "Checking build root"
 test_image_content "${BOARD_ROOT}"