diff --git a/docs/software/nrf52-TODO.md b/docs/software/nrf52-TODO.md
index 500180d03..55b781d23 100644
--- a/docs/software/nrf52-TODO.md
+++ b/docs/software/nrf52-TODO.md
@@ -59,8 +59,6 @@ Needed to be fully functional at least at the same level of the ESP32 boards. At
 
 Nice ideas worth considering someday...
 
-- Use flego to me an iOS/linux app? https://felgo.com/doc/qt/qtbluetooth-index/ or
-- Use flutter to make an iOS/linux app? https://github.com/Polidea/FlutterBleLib
 - enable monitor mode debugging (need to use real jlink): https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/monitor-mode-debugging-with-j-link-and-gdbeclipse
 - Improve efficiency of PeriodicTimer by only checking the next queued timer event, and carefully sorting based on schedule
 - make a Mfg Controller and device under test classes as examples of custom app code for third party devs. Make a post about this. Use a custom payload type code. Have device under test send a broadcast with max hopcount of 0 for the 'mfgcontroller' payload type. mfg controller will read SNR and reply. DOT will declare failure/success and switch to the regular app screen.
diff --git a/src/PowerFSM.cpp b/src/PowerFSM.cpp
index 1e9adbec9..c495cd27f 100644
--- a/src/PowerFSM.cpp
+++ b/src/PowerFSM.cpp
@@ -26,60 +26,70 @@ static void sdsEnter()
 
 #include "error.h"
 
+static uint32_t secsSlept;
+
 static void lsEnter()
 {
     DEBUG_MSG("lsEnter begin, ls_secs=%u\n", radioConfig.preferences.ls_secs);
     screen.setOn(false);
+    secsSlept = 0; // How long have we been sleeping this time
 
     DEBUG_MSG("lsEnter end\n");
 }
 
 static void lsIdle()
 {
-    DEBUG_MSG("lsIdle begin ls_secs=%u\n", radioConfig.preferences.ls_secs);
+    // DEBUG_MSG("lsIdle begin ls_secs=%u\n", radioConfig.preferences.ls_secs);
 
 #ifndef NO_ESP32
-    uint32_t secsSlept = 0;
     esp_sleep_source_t wakeCause = ESP_SLEEP_WAKEUP_UNDEFINED;
-    bool reached_ls_secs = false;
 
-    while (!reached_ls_secs) {
+    // Do we have more sleeping to do?
+    if (secsSlept < radioConfig.preferences.ls_secs) {
         // Briefly come out of sleep long enough to blink the led once every few seconds
-        uint32_t sleepTime = 5;
+        uint32_t sleepTime = 30;
 
-        setLed(false); // Never leave led on while in light sleep
-        wakeCause = doLightSleep(sleepTime * 1000LL);
-        if (wakeCause != ESP_SLEEP_WAKEUP_TIMER)
-            break;
+        // If some other service would stall sleep, don't let sleep happen yet
+        if (doPreflightSleep()) {
+            setLed(false); // Never leave led on while in light sleep
+            wakeCause = doLightSleep(sleepTime * 1000LL);
 
-        setLed(true); // briefly turn on led
-        doLightSleep(1);
-        if (wakeCause != ESP_SLEEP_WAKEUP_TIMER)
-            break;
+            if (wakeCause == ESP_SLEEP_WAKEUP_TIMER) {
+                // Normal case: timer expired, we should just go back to sleep ASAP
 
-        secsSlept += sleepTime;
-        reached_ls_secs = secsSlept >= radioConfig.preferences.ls_secs;
-    }
-    setLed(false);
+                setLed(true);                // briefly turn on led
+                wakeCause = doLightSleep(1); // leave led on for 1ms
 
-    if (reached_ls_secs) {
-        // stay in LS mode but let loop check whatever it wants
-        DEBUG_MSG("reached ls_secs, servicing loop()\n");
-    } else {
-        DEBUG_MSG("wakeCause %d\n", wakeCause);
+                secsSlept += sleepTime;
+                // DEBUG_MSG("sleeping, flash led!\n");
+            }
+            if (wakeCause == ESP_SLEEP_WAKEUP_UART) {
+                // Not currently used (because uart triggers in hw have problems)
+                powerFSM.trigger(EVENT_SERIAL_CONNECTED);
+            } else {
+                // We woke for some other reason (button press, uart, device interrupt)
+                //uint64_t status = esp_sleep_get_ext1_wakeup_status();
+                DEBUG_MSG("wakeCause %d\n", wakeCause);
 
 #ifdef BUTTON_PIN
-        bool pressed = !digitalRead(BUTTON_PIN);
+                bool pressed = !digitalRead(BUTTON_PIN);
 #else
-        bool pressed = false;
+                bool pressed = false;
 #endif
-        if (pressed) // If we woke because of press, instead generate a PRESS event.
-        {
-            powerFSM.trigger(EVENT_PRESS);
-        } else {
-            // Otherwise let the NB state handle the IRQ (and that state will handle stuff like IRQs etc)
-            powerFSM.trigger(EVENT_WAKE_TIMER);
+                if (pressed) // If we woke because of press, instead generate a PRESS event.
+                {
+                    powerFSM.trigger(EVENT_PRESS);
+                } else {
+                    // Otherwise let the NB state handle the IRQ (and that state will handle stuff like IRQs etc)
+                    powerFSM.trigger(EVENT_WAKE_TIMER);
+                }
+            }
         }
+    } else {
+        // Time to stop sleeping!
+        setLed(false);
+        DEBUG_MSG("reached ls_secs, servicing loop()\n");
+        powerFSM.trigger(EVENT_WAKE_TIMER);
     }
 #endif
 }
diff --git a/src/configuration.h b/src/configuration.h
index bc64d3187..4759dfc73 100644
--- a/src/configuration.h
+++ b/src/configuration.h
@@ -258,7 +258,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #ifdef NO_ESP32
 #define USE_SEGGER
+#else
+#define SERIAL0_RX_GPIO 3 // Always GPIO3 on ESP32
 #endif
+
 #ifdef USE_SEGGER
 #include "SEGGER_RTT.h"
 #define DEBUG_MSG(...) SEGGER_RTT_printf(0, __VA_ARGS__)
diff --git a/src/mesh/NodeDB.cpp b/src/mesh/NodeDB.cpp
index 86b5bda84..37233a3a0 100644
--- a/src/mesh/NodeDB.cpp
+++ b/src/mesh/NodeDB.cpp
@@ -124,7 +124,7 @@ void NodeDB::init()
     // default to no GPS, until one has been found by probing
     myNodeInfo.has_gps = false;
     myNodeInfo.message_timeout_msec = FLOOD_EXPIRE_TIME;
-    myNodeInfo.min_app_version = 167;
+    myNodeInfo.min_app_version = 172;
     generatePacketId(); // FIXME - ugly way to init current_packet_id;
 
     // Init our blank owner info to reasonable defaults
diff --git a/src/mesh/RadioInterface.cpp b/src/mesh/RadioInterface.cpp
index c7edf74de..43d9a6696 100644
--- a/src/mesh/RadioInterface.cpp
+++ b/src/mesh/RadioInterface.cpp
@@ -24,7 +24,7 @@ separated by 2.16 MHz with respect to the adjacent channels. Channel zero starts
 // 1kb was too small
 #define RADIO_STACK_SIZE 4096
 
-RadioInterface::RadioInterface() : txQueue(MAX_TX_QUEUE)
+RadioInterface::RadioInterface()
 {
     assert(sizeof(PacketHeader) == 4 || sizeof(PacketHeader) == 16); // make sure the compiler did what we expected
 
diff --git a/src/mesh/RadioInterface.h b/src/mesh/RadioInterface.h
index 64222a76a..0617592ac 100644
--- a/src/mesh/RadioInterface.h
+++ b/src/mesh/RadioInterface.h
@@ -59,7 +59,6 @@ class RadioInterface : protected NotifiedWorkerThread
 
   protected:
     MeshPacket *sendingPacket = NULL; // The packet we are currently sending
-    PointerQueue<MeshPacket> txQueue;
     uint32_t lastTxStart = 0L;
 
     /**
diff --git a/src/mesh/RadioLibInterface.cpp b/src/mesh/RadioLibInterface.cpp
index 53f99aae9..5239f8f60 100644
--- a/src/mesh/RadioLibInterface.cpp
+++ b/src/mesh/RadioLibInterface.cpp
@@ -134,7 +134,7 @@ bool RadioLibInterface::canSleep()
 {
     bool res = txQueue.isEmpty();
     if (!res) // only print debug messages if we are vetoing sleep
-        DEBUG_MSG("radio wait to sleep, txEmpty=%d\n", txQueue.isEmpty());
+        DEBUG_MSG("radio wait to sleep, txEmpty=%d\n", res);
 
     return res;
 }
@@ -173,11 +173,13 @@ void RadioLibInterface::loop()
     case ISR_TX:
         handleTransmitInterrupt();
         startReceive();
+        // DEBUG_MSG("tx complete - starting timer\n");
         startTransmitTimer();
         break;
     case ISR_RX:
         handleReceiveInterrupt();
         startReceive();
+        // DEBUG_MSG("rx complete - starting timer\n");
         startTransmitTimer();
         break;
     case TRANSMIT_DELAY_COMPLETED:
@@ -192,6 +194,8 @@ void RadioLibInterface::loop()
                 assert(txp);
                 startSend(txp);
             }
+        } else {
+            // DEBUG_MSG("done with txqueue\n");
         }
         break;
     default:
@@ -216,7 +220,7 @@ void RadioLibInterface::startTransmitTimer(bool withDelay)
         uint32_t delay =
             !withDelay ? 1 : random(MIN_TX_WAIT_MSEC, MAX_TX_WAIT_MSEC); // See documentation for loop() wrt these values
                                                                          // DEBUG_MSG("xmit timer %d\n", delay);
-
+        // DEBUG_MSG("delaying %u\n", delay);
         setPeriod(delay);
     }
 }
diff --git a/src/mesh/RadioLibInterface.h b/src/mesh/RadioLibInterface.h
index 1a0e5f450..6619337ba 100644
--- a/src/mesh/RadioLibInterface.h
+++ b/src/mesh/RadioLibInterface.h
@@ -29,6 +29,8 @@ class RadioLibInterface : public RadioInterface, private PeriodicTask
      */
     uint32_t rxBad = 0, rxGood = 0, txGood = 0;
 
+    PointerQueue<MeshPacket> txQueue = PointerQueue<MeshPacket>(MAX_TX_QUEUE);
+
   protected:
     float bw = 125;
     uint8_t sf = 9;
diff --git a/src/sleep.cpp b/src/sleep.cpp
index 18462de79..8cb0f6798 100644
--- a/src/sleep.cpp
+++ b/src/sleep.cpp
@@ -14,6 +14,7 @@
 #include "esp_pm.h"
 #include "rom/rtc.h"
 #include <driver/rtc_io.h>
+#include <driver/uart.h>
 
 #include "BluetoothUtil.h"
 
@@ -111,8 +112,7 @@ void initDeepSleep()
 #endif
 }
 
-/// return true if sleep is allowed
-static bool doPreflightSleep()
+bool doPreflightSleep()
 {
     if (preflightSleep.notifyObservers(NULL) != 0)
         return false; // vetoed
@@ -257,6 +257,17 @@ esp_sleep_wakeup_cause_t doLightSleep(uint64_t sleepMsec) // FIXME, use a more r
     gpio_pullup_en((gpio_num_t)BUTTON_PIN);
 #endif
 
+#ifdef SERIAL0_RX_GPIO
+    // We treat the serial port as a GPIO for a fast/low power way of waking, if we see a rising edge that means
+    // someone started to send something
+
+    // Alas - doesn't work reliably, instead need to use the uart specific version (which burns a little power)
+    // FIXME: gpio 3 is RXD for serialport 0 on ESP32
+    // Send a few Z characters to wake the port
+    gpio_wakeup_enable((gpio_num_t)SERIAL0_RX_GPIO, GPIO_INTR_LOW_LEVEL);
+    // uart_set_wakeup_threshold(UART_NUM_0, 3);
+    // esp_sleep_enable_uart_wakeup(0);
+#endif
 #ifdef BUTTON_PIN
     gpio_wakeup_enable((gpio_num_t)BUTTON_PIN, GPIO_INTR_LOW_LEVEL); // when user presses, this button goes low
 #endif
diff --git a/src/sleep.h b/src/sleep.h
index b3446882a..66eafa611 100644
--- a/src/sleep.h
+++ b/src/sleep.h
@@ -19,6 +19,9 @@ void initDeepSleep();
 void setCPUFast(bool on);
 void setLed(bool ledOn);
 
+/** return true if sleep is allowed right now */
+bool doPreflightSleep();
+
 extern int bootCount;
 
 // is bluetooth sw currently running?