[moblab] Uprev the moblab stable image.

BUG=chromium:1017554
TEST=None

Change-Id: I1e3752eb312d414e469c219cf3765443568bc562
Previous-Reviewed-on: https://chromium-review.googlesource.com/1877839
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
(cherry picked from commit 8453da312f3dec8be3868acff88edbf22040cd9a)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/1879648
Reviewed-by: Keith Haddow <haddowk@chromium.org>
Commit-Queue: Keith Haddow <haddowk@chromium.org>
Tested-by: Keith Haddow <haddowk@chromium.org>
diff --git a/moblab_config.ini b/moblab_config.ini
index dcbeb9f..6897402 100644
--- a/moblab_config.ini
+++ b/moblab_config.ini
@@ -35,7 +35,7 @@
 cts_results_server:
 # In moblab, this paramater is empty and uses the image bucket by default.
 results_storage_server:
-stable_cros_version: R75-12105.100.0
+stable_cros_version: R77-12371.75.0
 devserver_dir = /usr/lib/devserver/
 
 # The pubsub topic the gs_offloader notification is sent to.