diff --git a/build_image b/build_image
index ccbea76496..d51791d2cc 100755
--- a/build_image
+++ b/build_image
@@ -182,10 +182,11 @@ then
 fi
 
 # Write out a version.txt file, this will be used by image_to_vm.sh
+split_ver "${COREOS_VERSION_ID}" SPLIT
 tee "${BUILD_DIR}/version.txt" <<EOF
-COREOS_BUILD=${COREOS_BUILD}
-COREOS_BRANCH=${COREOS_BRANCH}
-COREOS_PATCH=${COREOS_PATCH}
+COREOS_BUILD=${SPLIT[0]}
+COREOS_BRANCH=${SPLIT[1]}
+COREOS_PATCH=${SPLIT[2]}
 COREOS_VERSION=${COREOS_VERSION_STRING}
 COREOS_VERSION_ID=${COREOS_VERSION_ID}
 COREOS_BUILD_ID="${COREOS_BUILD_ID}"
diff --git a/common.sh b/common.sh
index 8d22d0aa65..2c037a7c18 100644
--- a/common.sh
+++ b/common.sh
@@ -172,6 +172,20 @@ cmp_ver() {
   return $?
 }
 
+# Split a semver into a 3 item array (major minor patch)
+# Usage: split_ver 1.2.3 NAME
+split_ver() {
+  local v="$1" n="$2"
+  v="${v%%-*}" # strip off pre-release suffix
+  v="${v%%+*}" # strip off build id suffix
+  v="${v//./ }"
+  local -a a="(${v})"
+  if [[ ${#a[@]} -ne 3 ]]; then
+    die "Invalid version string '$1'"
+  fi
+  declare -g -a ${n}="(${v})"
+}
+
 # repo source root inside the chroot, usually mounted from the outside.
 CHROOT_TRUNK_DIR="/mnt/host/source"