vboot: add debug message for VB_SCREEN_OS_BROKEN

This change adds a fallback text for VB_SCREEN_OS_BROKEN, which is shown
when the screen is not supported.

BUG=chromium:501060
BRANCH=master
TEST=Tested on Samus
CQ-DEPEND=CL:304404

Change-Id: I0f35ec873532fcfe6782ccff89d54798152f7fb3
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/305252
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
diff --git a/src/vboot/screens.c b/src/vboot/screens.c
index dd3836f..7e512dc 100644
--- a/src/vboot/screens.c
+++ b/src/vboot/screens.c
@@ -336,6 +336,12 @@
 		.mesg = "OS verification is ON\n"
 			"Your system will reboot and local data will be cleared.\n",
 	},
+	{
+		.id = VB_SCREEN_OS_BROKEN,
+		.draw = NULL,
+		.mesg = "Chrome OS may be broken.\n"
+			"Remove media and initiate recovery.\n",
+	},
 };
 
 static const struct vboot_screen_descriptor *get_screen_descriptor(uint32_t id)