diff --git a/adb/services.cpp b/adb/services.cpp
index dbf71d3..ca34556 100644
--- a/adb/services.cpp
+++ b/adb/services.cpp
@@ -150,6 +150,7 @@
 
     sync();
 
+    if (!reboot_arg || !reboot_arg[0]) reboot_arg = "adb";
     std::string reboot_string = android::base::StringPrintf("reboot,%s", reboot_arg);
     if (!android::base::SetProperty(ANDROID_RB_PROPERTY, reboot_string)) {
         WriteFdFmt(fd, "reboot (%s) failed\n", reboot_string.c_str());
diff --git a/bootstat/boot_reason_test.sh b/bootstat/boot_reason_test.sh
index 7b0b0da..d789808 100755
--- a/bootstat/boot_reason_test.sh
+++ b/bootstat/boot_reason_test.sh
@@ -427,8 +427,8 @@
   adb reboot >&2
   wait_for_screen
   EXPECT_PROPERTY sys.boot.reason reboot,factory_reset
-  EXPECT_PROPERTY persist.sys.boot.reason reboot,
-  report_bootstat_logs reboot,factory_reset reboot, \
+  EXPECT_PROPERTY persist.sys.boot.reason "reboot,.*"
+  report_bootstat_logs reboot,factory_reset reboot, reboot,adb \
     "-bootstat: Failed to read /data/misc/bootstat/build_date: No such file or directory" \
     "-bootstat: Failed to parse boot time record: /data/misc/bootstat/build_date"
 }
@@ -599,6 +599,38 @@
   report_bootstat_logs shutdown,userrequested
 }
 
+[ "USAGE: test_shell_reboot
+
+shell reboot test:
+- adb shell reboot
+- (wait until screen is up, boot has completed)
+- adb shell getprop sys.boot.reason
+- NB: should report reboot,shell" ]
+test_shell_reboot() {
+  echo "INFO: expected duration of ${TEST} test roughly 45 seconds" >&2
+  adb shell reboot
+  wait_for_screen
+  EXPECT_PROPERTY sys.boot.reason reboot,shell
+  EXPECT_PROPERTY persist.sys.boot.reason reboot,shell
+  report_bootstat_logs reboot,shell
+}
+
+[ "USAGE: test_adb_reboot
+
+adb reboot test:
+- adb reboot
+- (wait until screen is up, boot has completed)
+- adb shell getprop sys.boot.reason
+- NB: should report reboot,adb" ]
+test_adb_reboot() {
+  echo "INFO: expected duration of ${TEST} test roughly 45 seconds" >&2
+  adb reboot
+  wait_for_screen
+  EXPECT_PROPERTY sys.boot.reason reboot,adb
+  EXPECT_PROPERTY persist.sys.boot.reason reboot,adb
+  report_bootstat_logs reboot,adb
+}
+
 [ "USAGE: ${0##*/} [-s SERIAL] [tests]
 
 Mainline executive to run the above tests" ]
@@ -650,7 +682,7 @@
   if [ -z "${2}" ]; then
     # Hard coded should shell fail to find them above (search/permission issues)
     eval set ota cold factory_reset hard battery unknown kernel_panic warm \
-             thermal_shutdown userrequested_shutdown
+             thermal_shutdown userrequested_shutdown shell_reboot adb_reboot
   fi
   if [ X"nothing" = X"${1}" ]; then
     shift 1
diff --git a/bootstat/bootstat.cpp b/bootstat/bootstat.cpp
index 418c711..a0a9307 100644
--- a/bootstat/bootstat.cpp
+++ b/bootstat/bootstat.cpp
@@ -202,6 +202,8 @@
   {"reboot,ota", 63},
   {"reboot,factory_reset", 64},
   {"reboot,", 65},
+  {"reboot,shell", 66},
+  {"reboot,adb", 67},
 };
 
 // Converts a string value representing the reason the system booted to an
diff --git a/reboot/reboot.c b/reboot/reboot.c
index 007dfba..f0cf40c 100644
--- a/reboot/reboot.c
+++ b/reboot/reboot.c
@@ -56,6 +56,7 @@
 
     if (argc > optind)
         optarg = argv[optind];
+    if (!optarg || !optarg[0]) optarg = "shell";
 
     prop_len = snprintf(property_val, sizeof(property_val), "%s,%s", cmd, optarg);
     if (prop_len >= sizeof(property_val)) {