diff --git a/bootstat/boot_reason_test.sh b/bootstat/boot_reason_test.sh
index 5425fd3..c42680c 100755
--- a/bootstat/boot_reason_test.sh
+++ b/bootstat/boot_reason_test.sh
@@ -22,6 +22,8 @@
 GREEN="${ESCAPE}[38;5;40m"
 RED="${ESCAPE}[38;5;196m"
 NORMAL="${ESCAPE}[0m"
+# Best guess to an average device's reboot time, refined as tests return
+DURATION_DEFAULT=45
 
 # Helper functions
 
@@ -57,12 +59,15 @@
   fi
 }
 
-[ "USAGE: checkDebugBuild
+[ "USAGE: checkDebugBuild [--noerror]
 
 Returns: true if device is a userdebug or eng release" ]
 checkDebugBuild() {
   if isDebuggable; then
     echo "INFO: '${TEST}' test requires userdebug build"
+  elif [ -n "${1}" ]; then
+    echo "WARNING: '${TEST}' test requires userdebug build"
+    false
   else
     echo "ERROR: '${TEST}' test requires userdebug build, skipping FAILURE"
     false
@@ -204,7 +209,7 @@
   return 0
 }
 
-[ "USAGE: EXPECT_PROPERTY <prop> <value>
+[ "USAGE: EXPECT_PROPERTY <prop> <value> [--allow_failure]
 
 Returns true if current return (regex) value is true and the result matches" ]
 EXPECT_PROPERTY() {
@@ -214,6 +219,7 @@
   shift 2
   val=`adb shell getprop ${property} 2>&1`
   EXPECT_EQ "${value}" "${val}" for Android property ${property} ||
+    [ -n "${1}" ] ||
     save_ret=${?}
   return ${save_ret}
 }
@@ -279,11 +285,44 @@
 Record start of test, preserve exit status" ]
 start_test() {
   save_ret=${?}
+  duration_prefix="~"
+  duration_estimate=1
   START=`date +%s`
   echo "${GREEN}[ RUN      ]${NORMAL} ${TEST} ${*}"
   return ${save_ret}
 }
 
+duration_sum_diff=0
+duration_num=0
+[ "USAGE: duration_test [[prefix]seconds]
+
+Report the adjusted and expected test duration" ]
+duration_test() {
+  duration_prefix=${1%%[0123456789]*}
+  if [ -z "${duration_prefix}" ]; then
+    duration_prefix="~"
+  fi
+  duration_estimate="${1#${duration_prefix}}"
+  if [ -z "${duration_estimate}" ]; then
+    duration_estimate="${DURATION_DEFAULT}"
+  fi
+  duration_new_estimate="${duration_estimate}"
+  if [ 0 -ne ${duration_num} ]; then
+    duration_new_estimate=`expr ${duration_new_estimate} + \
+      \( ${duration_num} / 2 + ${duration_sum_diff} \) / ${duration_num}`
+    # guard against catastrophe
+    if [ -z "${duration_new_estimate}" ]; then
+      duration_new_estimate=${duration_estimate}
+    fi
+  fi
+  # negative values are so undignified
+  if [ 0 -ge ${duration_new_estimate} ]; then
+    duration_new_estimate=1
+  fi
+  echo "INFO: expected duration of '${TEST}' test" \
+       "${duration_prefix}`format_duration ${duration_new_estimate}`" >&2
+}
+
 [ "USAGE: end_test [message]
 
 Document duration and success of test, preserve exit status" ]
@@ -291,9 +330,16 @@
   save_ret=${?}
   END=`date +%s`
   duration=`expr ${END} - ${START} 2>/dev/null`
-  [ 0 = ${duration} ] ||
+  [ 0 -ge ${duration} ] ||
     echo "INFO: '${TEST}' test duration `format_duration ${duration}`" >&2
   if [ ${save_ret} = 0 ]; then
+    if [ 0 -lt ${duration} -a 0 -lt ${duration_estimate} -a \( \
+           X"~" = X"${duration_prefix}" -o \
+           ${duration_estimate} -gt ${duration} \) ]; then
+      duration_sum_diff=`expr ${duration_sum_diff} + \
+                              ${duration} - ${duration_estimate}`
+      duration_num=`expr ${duration_num} + 1`
+    fi
     echo "${GREEN}[       OK ]${NORMAL} ${TEST} ${*}"
   else
     echo "${RED}[  FAILED  ]${NORMAL} ${TEST} ${*}"
@@ -372,6 +418,7 @@
 - adb shell getprop sys.boot.reason (system reason)
 - NB: all should have a value that is compliant with our known set." ]
 test_properties() {
+  duration_test 1
   wait_for_screen
   retval=0
   check_set="ro.boot.bootreason persist.sys.boot.reason sys.boot.reason"
@@ -410,7 +457,7 @@
 Decision to change the build itself rather than trick bootstat by
 rummaging through its data files was made." ]
 test_ota() {
-  echo "INFO: expected duration of '${TEST}' test >`format_duration 300`" >&2
+  duration_test ">300"
   echo "      extended by build and flashing times" >&2
   if [ -z "${TARGET_PRODUCT}" -o \
        -z "${ANDROID_PRODUCT_OUT}" -o \
@@ -451,7 +498,7 @@
 fast and fake (touch build_date on device to make it different)" ]
 test_optional_ota() {
   checkDebugBuild || return
-  echo "INFO: expected duration of '${TEST}' test ~`format_duration 45`" >&2
+  duration_test
   adb shell su root touch /data/misc/bootstat/build_date >&2
   adb reboot ota
   wait_for_screen
@@ -472,11 +519,11 @@
 as a means of checking sanity and any persistent side effect of the
 other tests." ]
 blind_reboot_test() {
+  duration_test
   case ${TEST} in
     bootloader | recovery | cold | hard | warm ) reason=${TEST} ;;
     *)                                           reason=reboot,${TEST} ;;
   esac
-  echo "INFO: expected duration of '${TEST}' test ~`format_duration 45`" >&2
   adb reboot ${TEST}
   wait_for_screen
   EXPECT_PROPERTY sys.boot.reason ${reason}
@@ -508,7 +555,7 @@
 a _real_ factory_reset is too destructive to the device." ]
 test_factory_reset() {
   checkDebugBuild || return
-  echo "INFO: expected duration of '${TEST}' test ~`format_duration 45`" >&2
+  duration_test
   adb shell su root rm /data/misc/bootstat/build_date >&2
   adb reboot >&2
   wait_for_screen
@@ -531,7 +578,7 @@
 
 For realz, and disruptive" ]
 test_optional_factory_reset() {
-  echo "INFO: expected duration of '${TEST}' test ~`format_duration 60`" >&2
+  duration_test 60
   if ! inFastboot; then
     adb reboot-bootloader
   fi
@@ -585,7 +632,7 @@
 - (replace set logd.kernel true to the above, and retry test)" ]
 test_battery() {
   checkDebugBuild || return
-  echo "INFO: expected duration of '${TEST}' test ~`format_duration 120`" >&2
+  duration_test 120
   enterPstore
   # Send it _many_ times to combat devices with flakey pstore
   for i in a b c d e f g h i j k l m n o p q r s t u v w x y z; do
@@ -626,7 +673,7 @@
 - adb shell getprop sys.boot.reason
 - NB: should report shutdown,battery" ]
 test_optional_battery() {
-  echo "INFO: expected duration of '${TEST}' test >`format_duration 60`" >&2
+  duration_test ">60"
   echo "      power on request" >&2
   adb shell setprop sys.powerctl shutdown,battery
   sleep 5
@@ -646,7 +693,7 @@
 - adb shell getprop sys.boot.reason
 - NB: should report shutdown,thermal,battery" ]
 test_optional_battery_thermal() {
-  echo "INFO: expected duration of '${TEST}' test >`format_duration 60`" >&2
+  duration_test ">60"
   echo "      power on request" >&2
   adb shell setprop sys.powerctl shutdown,thermal,battery
   sleep 5
@@ -678,7 +725,7 @@
 - NB: should report kernel_panic,sysrq" ]
 test_kernel_panic() {
   checkDebugBuild || return
-  echo "INFO: expected duration of '${TEST}' test >`format_duration 120`" >&2
+  duration_test ">90"
   panic_msg="kernel_panic,sysrq"
   enterPstore || panic_msg="\(kernel_panic,sysrq\|kernel_panic\)"
   echo c | adb shell su root tee /proc/sysrq-trigger >/dev/null
@@ -709,7 +756,7 @@
 - adb shell getprop sys.boot.reason
 - NB: should report shutdown,thermal" ]
 test_thermal_shutdown() {
-  echo "INFO: expected duration of '${TEST}' test >`format_duration 60`" >&2
+  durtion_test ">60"
   echo "      power on request" >&2
   adb shell setprop sys.powerctl shutdown,thermal
   sleep 5
@@ -729,7 +776,7 @@
 - adb shell getprop sys.boot.reason
 - NB: should report shutdown,userrequested" ]
 test_userrequested_shutdown() {
-  echo "INFO: expected duration of '${TEST}' test >`format_duration 60`" >&2
+  duration_test ">60"
   echo "      power on request" >&2
   adb shell setprop sys.powerctl shutdown,userrequested
   sleep 5
@@ -748,7 +795,7 @@
 - adb shell getprop sys.boot.reason
 - NB: should report reboot,shell" ]
 test_shell_reboot() {
-  echo "INFO: expected duration of '${TEST}' test ~`format_duration 45`" >&2
+  duration_test
   adb shell reboot
   wait_for_screen
   EXPECT_PROPERTY sys.boot.reason reboot,shell
@@ -764,7 +811,7 @@
 - adb shell getprop sys.boot.reason
 - NB: should report reboot,adb" ]
 test_adb_reboot() {
-  echo "INFO: expected duration of '${TEST}' test ~`format_duration 45`" >&2
+  duration_test
   adb reboot
   wait_for_screen
   EXPECT_PROPERTY sys.boot.reason reboot,adb
@@ -781,14 +828,18 @@
 - NB: should report reboot,its_just_so_hard
 - NB: expect log \"... I bootstat: Unknown boot reason: reboot,its_just_so_hard\"" ]
 test_Its_Just_So_Hard_reboot() {
-  checkDebugBuild || return
-  echo "INFO: expected duration of '${TEST}' test ~`format_duration 45`" >&2
+  duration_test
   adb shell 'reboot "Its Just So Hard"'
   wait_for_screen
   EXPECT_PROPERTY sys.boot.reason reboot,its_just_so_hard
   EXPECT_PROPERTY persist.sys.boot.reason "reboot,Its Just So Hard"
   adb shell su root setprop persist.sys.boot.reason reboot,its_just_so_hard
-  EXPECT_PROPERTY persist.sys.boot.reason reboot,its_just_so_hard
+  if checkDebugBuild; then
+    flag=""
+  else
+    flag="--allow_failure"
+  fi
+  EXPECT_PROPERTY persist.sys.boot.reason reboot,its_just_so_hard ${flag}
   report_bootstat_logs reboot,its_just_so_hard
 }