diff --git a/main/main.ino b/main/main.ino
index 18d973b..837640f 100644
--- a/main/main.ino
+++ b/main/main.ino
@@ -101,9 +101,45 @@ void sleep() {
 #endif
 }
 
+void printHex2(unsigned v) {
+    v &= 0xff;
+    if (v < 16)
+        Serial.print('0');
+    Serial.print(v, HEX);
+}
+
+
 void callback(uint8_t message) {
   if (EV_JOINING == message) screen_print("Joining TTN...\n");
-  if (EV_JOINED == message) screen_print("TTN joined!\n");
+  if (EV_JOINED == message) {
+    screen_print("TTN joined!\n");
+
+    Serial.println(F("EV_JOINED"));
+
+    u4_t netid = 0;
+    devaddr_t devaddr = 0;
+    u1_t nwkKey[16];
+    u1_t artKey[16];
+    LMIC_getSessionKeys(&netid, &devaddr, nwkKey, artKey);
+    Serial.print("netid: ");
+    Serial.println(netid, DEC);
+    Serial.print("devaddr: ");
+    Serial.println(devaddr, HEX);
+    Serial.print("AppSKey: ");
+    for (size_t i=0; i<sizeof(artKey); ++i) {
+      if (i != 0)
+          Serial.print("-");
+      printHex2(artKey[i]);
+    }
+    Serial.println("");
+    Serial.print("NwkSKey: ");
+    for (size_t i=0; i<sizeof(nwkKey); ++i) {
+      if (i != 0)
+              Serial.print("-");
+      printHex2(nwkKey[i]);
+    }
+    Serial.println();
+  }
   if (EV_JOIN_FAILED == message) screen_print("TTN join failed\n");
   if (EV_REJOIN_FAILED == message) screen_print("TTN rejoin failed\n");
   if (EV_RESET == message) screen_print("Reset TTN connection\n");
diff --git a/main/ttn.ino b/main/ttn.ino
index 60b80f2..c666f33 100644
--- a/main/ttn.ino
+++ b/main/ttn.ino
@@ -92,6 +92,11 @@ void onEvent(ev_t event) {
         #ifdef SINGLE_CHANNEL_GATEWAY
         forceTxSingleChannelDr();
         #endif
+
+        // Disable link check validation (automatically enabled
+        // during join, but because slow data rates change max TX
+        // size, we don't use it in this example.
+        LMIC_setLinkCheckMode(0);
         break;
     case EV_TXCOMPLETE:
         Serial.println(F("EV_TXCOMPLETE (inc. RX win. wait)"));
@@ -148,16 +153,6 @@ void ttn_join() {
     LMIC_setClockError(MAX_CLOCK_ERROR * CLOCK_ERROR / 100);
     #endif
 
-    #if defined(USE_ABP)
-
-        // Set static session parameters. Instead of dynamically establishing a session
-        // by joining the network, precomputed session parameters are be provided.
-        uint8_t appskey[sizeof(APPSKEY)];
-        uint8_t nwkskey[sizeof(NWKSKEY)];
-        memcpy_P(appskey, APPSKEY, sizeof(APPSKEY));
-        memcpy_P(nwkskey, NWKSKEY, sizeof(NWKSKEY));
-        LMIC_setSession(0x1, DEVADDR, nwkskey, appskey);
-
         #if defined(CFG_eu868)
 
             // Set up the channels used by the Things Network, which corresponds
@@ -196,9 +191,6 @@ void ttn_join() {
         // Disable link check validation
         LMIC_setLinkCheckMode(0);
 
-        // TTN uses SF9 for its RX2 window.
-        LMIC.dn2Dr = DR_SF9;
-
         #ifdef SINGLE_CHANNEL_GATEWAY
         forceTxSingleChannelDr();
         #else
@@ -206,21 +198,34 @@ void ttn_join() {
         ttn_sf(LORAWAN_SF);
         #endif
 
+    #if defined(USE_ABP)
+
+        // Set static session parameters. Instead of dynamically establishing a session
+        // by joining the network, precomputed session parameters are be provided.
+        uint8_t appskey[sizeof(APPSKEY)];
+        uint8_t nwkskey[sizeof(NWKSKEY)];
+        memcpy_P(appskey, APPSKEY, sizeof(APPSKEY));
+        memcpy_P(nwkskey, NWKSKEY, sizeof(NWKSKEY));
+        LMIC_setSession(0x1, DEVADDR, nwkskey, appskey);
+
+        // TTN uses SF9 for its RX2 window.
+        LMIC.dn2Dr = DR_SF9;
+
         // Trigger a false joined
         _ttn_callback(EV_JOINED);
 
     #elif defined(USE_OTAA)
 
       #ifdef SINGLE_CHANNEL_GATEWAY
-      // Make LMiC initialize the default channels, choose a channel, and
-      // schedule the OTAA join
-      LMIC_startJoining();
-
       // LMiC will already have decided to send on one of the 3 default
       // channels; ensure it uses the one we want
       LMIC.txChnl = SINGLE_CHANNEL_GATEWAY;
       #endif
 
+      // Make LMiC initialize the default channels, choose a channel, and
+      // schedule the OTAA join
+      LMIC_startJoining();
+
     #endif
 }