Merge "Allow ROOTFS to use environment variables"
diff --git a/net/test/run_net_test.sh b/net/test/run_net_test.sh
index 4ae7705..8249767 100755
--- a/net/test/run_net_test.sh
+++ b/net/test/run_net_test.sh
@@ -69,7 +69,7 @@
 NUMTAPINTERFACES=0
 
 # The root filesystem disk image we'll use.
-ROOTFS=net_test.rootfs.20150203
+ROOTFS=${ROOTFS:-net_test.rootfs.20150203}
 COMPRESSED_ROOTFS=$ROOTFS.xz
 URL=https://dl.google.com/dl/android/$COMPRESSED_ROOTFS