diff --git a/adb/commandline.c b/adb/commandline.c
index a927423..27a1754 100644
--- a/adb/commandline.c
+++ b/adb/commandline.c
@@ -144,12 +144,15 @@
         "  adb bugreport                - return all information from the device\n"
         "                                 that should be included in a bug report.\n"
         "\n"
-        "  adb backup [-f <file>] [-apk|-noapk] [-shared|-noshared] [-all] [-system|-nosystem] [<packages...>]\n"
+        "  adb backup [-f <file>] [-apk|-noapk] [-obb|-noobb] [-shared|-noshared] [-all] [-system|-nosystem] [<packages...>]\n"
         "                               - write an archive of the device's data to <file>.\n"
         "                                 If no -f option is supplied then the data is written\n"
         "                                 to \"backup.ab\" in the current directory.\n"
         "                                 (-apk|-noapk enable/disable backup of the .apks themselves\n"
         "                                    in the archive; the default is noapk.)\n"
+        "                                 (-obb|-noobb enable/disable backup of any installed apk expansion\n"
+        "                                    (aka .obb) files associated with each application; the default\n"
+        "                                    is noobb.)\n"
         "                                 (-shared|-noshared enable/disable backup of the device's\n"
         "                                    shared storage / SD card contents; the default is noshared.)\n"
         "                                 (-all means to back up all installed applications)\n"