Use the HWID from the firmware as the hardware class, if available.

hardware_class

Index: hardware_class
diff --git a/hardware_class b/hardware_class
index c99db9b9e57edaa729f6fd0f962590a3bbd9b1c7..91360766677d555acb12716346f4570fb79a0a0d 100755
--- a/hardware_class
+++ b/hardware_class
@@ -8,49 +8,69 @@
 # qualification ID) of this device, or "unknown" if it can't determine
 # the hardware class.
 
-# TODO(petkov): The hardware qualification ID is not available on
-# systems yet, so the script uses alternative ways to identify
-# different system classes (e.g., the WiFi adapter PCI vendor and
-# device IDs). Switch the script to use real hardware qualification ID
-# when that becomes available.
+# TODO(petkov): If the hardware qualification ID is not available on
+# the systems, the script uses alternative ways to identify different
+# system classes (e.g., the WiFi adapter PCI vendor and device
+# IDs). Switch the script to use only real hardware qualification ID
+# when that becomes available on all systems.
+
+HARDWARE_CLASS=
+readonly HWID_PATH=/sys/bus/platform/devices/chromeos_acpi/HWID
 
 # Appends a new component ID to the hardware class. Separates IDs with
 # dashes.
 append_class() {
+  [ -n "$1" ] || return
   [ -n "$HARDWARE_CLASS" ] && HARDWARE_CLASS="${HARDWARE_CLASS}-"
   HARDWARE_CLASS="${HARDWARE_CLASS}$1"
 }
 
+hwid() {
+  [ -r  "$HWID_PATH" ] || return
+  local acpihwid
+  acpihwid=$(cat "$HWID_PATH")
+  [ -n "$acpihwid" ] || return
+  append_class "$acpihwid"
+}
+
 # Adds the CPU family, model and stepping info, if available, to the
 # class.
 cpu() {
   [ -r /proc/cpuinfo ] || return
-  FAMILY=`grep -m1 '^cpu family' /proc/cpuinfo \
-            | sed 's/cpu family\s\+:\s\+\([0-9]\+\)$/\1/'`
-  MODEL=`grep -m1 '^model' /proc/cpuinfo \
-           | sed 's/model\s\+:\s\+\([0-9]\+\)$/\1/'`
-  STEPPING=`grep -m1 '^stepping' /proc/cpuinfo \
-              | sed 's/stepping\s\+:\s\+\([0-9]\+\)$/\1/'`
-  if [ -n "$FAMILY" ] && [ -n "$MODEL" ] && [ -n "$STEPPING" ]; then
-    append_class "cpu/$FAMILY:$MODEL:$STEPPING"
+  local family
+  family=$(grep -m1 '^cpu family' /proc/cpuinfo \
+    | sed 's/cpu family\s\+:\s\+\([0-9]\+\)$/\1/')
+  local model
+  model=$(grep -m1 '^model' /proc/cpuinfo \
+    | sed 's/model\s\+:\s\+\([0-9]\+\)$/\1/')
+  local stepping
+  stepping=$(grep -m1 '^stepping' /proc/cpuinfo \
+    | sed 's/stepping\s\+:\s\+\([0-9]\+\)$/\1/')
+  if [ -n "$family" ] && [ -n "$model" ] && [ -n "$stepping" ]; then
+    append_class "cpu/$family:$model:$stepping"
   fi
 }
 
 # Adds the wlan0 PCI vendor and device ID, if available, to the class.
 wlan() {
-  WLAN_DEV=/sys/class/net/wlan0/device
-  if [ -r $WLAN_DEV/vendor ] && [ -r $WLAN_DEV/device ]; then
-    WLAN_ID=`paste -d ':' $WLAN_DEV/vendor $WLAN_DEV/device | sed s/0x//g`
-    append_class "wlan0/$WLAN_ID"
+  local dev=/sys/class/net/wlan0/device
+  if [ -r $dev/vendor ] && [ -r $dev/device ]; then
+    local id
+    id=$(paste -d ':' $dev/vendor $dev/device | sed s/0x//g)
+    append_class "wlan0/$id"
   fi
 }
 
+main() {
+  hwid
+  # If the HWID is not available, use system component IDs.
+  if [ -z "$HARDWARE_CLASS" ]; then
+    cpu
+    wlan
+    [ -z "$HARDWARE_CLASS" ] && HARDWARE_CLASS=unknown
+  fi
 
-HARDWARE_CLASS=
-
-cpu
-wlan
-
-[ -z "$HARDWARE_CLASS" ] && HARDWARE_CLASS=unknown
+  echo $HARDWARE_CLASS
+}
 
-echo $HARDWARE_CLASS
+main $@