diff --git a/include/timesync.h b/include/timesync.h
index 498952c1..286d82e7 100644
--- a/include/timesync.h
+++ b/include/timesync.h
@@ -7,7 +7,7 @@
 #include "timekeeper.h"
 
 //#define TIME_SYNC_TRIGGER 100 // threshold for time sync [milliseconds]
-#define TIME_SYNC_FRAME_LENGTH 0x05 // timeserver answer frame length [bytes]
+#define TIME_SYNC_FRAME_LENGTH 0x06 // timeserver answer frame length [bytes]
 #define TIME_SYNC_FIXUP 4 // calibration to fixup processing time [milliseconds]
 
 void timesync_init(void);
diff --git a/src/lorawan.cpp b/src/lorawan.cpp
index e82ac1f5..b5e941cb 100644
--- a/src/lorawan.cpp
+++ b/src/lorawan.cpp
@@ -265,9 +265,9 @@ void onEvent(ev_t ev) {
 
 #if (TIME_SYNC_LORASERVER)
           // timesync answer -> call timesync processor
-          if ((LMIC.frame[LMIC.dataBeg - 1] >= TIMEANSWERPORT_MIN) &&
-              (LMIC.frame[LMIC.dataBeg - 1] <= TIMEANSWERPORT_MAX)) {
-            recv_timesync_ans(LMIC.frame[LMIC.dataBeg - 1],
+          if ((LMIC.frame[LMIC.dataBeg] >= TIMEANSWERPORT_MIN) &&
+              (LMIC.frame[LMIC.dataBeg] <= TIMEANSWERPORT_MAX)) {
+            recv_timesync_ans(LMIC.frame[LMIC.dataBeg],
                               LMIC.frame + LMIC.dataBeg, LMIC.dataLen);
             break;
           }
diff --git a/src/timesync.cpp b/src/timesync.cpp
index 940696c5..488561c2 100644
--- a/src/timesync.cpp
+++ b/src/timesync.cpp
@@ -174,15 +174,15 @@ int recv_timesync_ans(uint8_t seq_no, uint8_t buf[], uint8_t buf_len) {
   else { // we received a probably valid time frame
 
     uint8_t k = seq_no % TIME_SYNC_SAMPLES;
-
+    uint8_t *timestamp_buf = buf+1;
     // the 5th byte contains the fractional seconds in 2^-8 second steps
     // (= 1/250th sec), we convert this to ms
-    uint16_t timestamp_msec = 4 * buf[4];
+    uint16_t timestamp_msec = 4 * timestamp_buf[4];
     // pointers to 4 bytes 4 bytes containing UTC seconds since unix epoch, msb
     uint32_t timestamp_sec, *timestamp_ptr;
 
     // convert buffer to uint32_t, octet order is big endian
-    timestamp_ptr = (uint32_t *)buf;
+    timestamp_ptr = (uint32_t *)timestamp_buf;
     // swap byte order from msb to lsb, note: this is platform dependent
     timestamp_sec = __builtin_bswap32(*timestamp_ptr);