prebuilt.conf: updating FULL_BINHOST

Change-Id: Ibecd74dc432ef448aa8e904b3e9c9aa85369f41b
diff --git a/overlay-arm-generic/prebuilt.conf b/overlay-arm-generic/prebuilt.conf
index d6b8198..7c05cc7 100644
--- a/overlay-arm-generic/prebuilt.conf
+++ b/overlay-arm-generic/prebuilt.conf
@@ -1,2 +1,2 @@
 
-FULL_BINHOST="gs://chromeos-prebuilt/board/arm-generic/full-R78-12439.0.0-rc2/packages/"
+FULL_BINHOST="gs://chromeos-prebuilt/board/arm-generic/full-R78-12440.0.0-rc1/packages/"