diff --git a/build_library/grub_install.sh b/build_library/grub_install.sh
index db83d614a1..d6f186f48b 100755
--- a/build_library/grub_install.sh
+++ b/build_library/grub_install.sh
@@ -43,7 +43,7 @@ GRUB_DIR="flatcar/grub/${FLAGS_target}"
 GRUB_SRC="/usr/lib/grub/${FLAGS_target}"
 
 # Modules required to boot a standard CoreOS configuration
-CORE_MODULES=( normal search test fat part_gpt search_fs_uuid gzio search_part_label terminal gptprio configfile memdisk tar echo read )
+CORE_MODULES=( normal search test fat part_gpt search_fs_uuid gzio search_part_label terminal gptprio configfile memdisk tar echo read btrfs )
 
 # Name of the core image, depends on target
 CORE_NAME=
@@ -141,10 +141,11 @@ done
 info "Generating ${GRUB_DIR}/load.cfg"
 # Include a small initial config in the core image to search for the ESP
 # by filesystem ID in case the platform doesn't provide the boot disk.
-# The existing $root value is given as a hint so it is searched first.
+# $root points to memdisk here so instead use hd0,gpt1 as a hint so it is
+# searched first.
 ESP_FSID=$(sudo grub-probe -t fs_uuid -d "${LOOP_DEV}p1")
 sudo_clobber "${ESP_DIR}/${GRUB_DIR}/load.cfg" <<EOF
-search.fs_uuid ${ESP_FSID} root \$root
+search.fs_uuid ${ESP_FSID} root hd0,gpt1
 set prefix=(memdisk)
 set
 EOF