Index: global_structures.h
===================================================================
--- global_structures.h	(revision 15419)
+++ global_structures.h	(working copy)
@@ -199,7 +199,7 @@
   u32 timestamps[NUM_SEQ_SAMPLES];
   int index;
   u16 ipids[NUM_SEQ_SAMPLES];
-  time_t lastboot; /* 0 means unknown */
+  long int lastboot; /* 0 means unknown */
 };
 
 /* Different kinds of Ipids. */
Index: osscan2.cc
===================================================================
--- osscan2.cc	(revision 15417)
+++ osscan2.cc	(working copy)
@@ -1886,6 +1886,7 @@
      5) Same with ~100/sec
   */
   if (hss->si.ts_seqclass == TS_SEQ_UNKNOWN && hss->si.responses >= 2) {
+    double lastboot = 0.0;
     avg_ts_hz = 0.0;
     for(i=0; i < hss->si.responses - 1; i++) {
       double dhz;
@@ -1897,30 +1898,32 @@
 
     if (avg_ts_hz > 0 && avg_ts_hz < 5.66) { /* relatively wide range because sampling time so short and frequency so slow */
       hss->si.ts_seqclass = TS_SEQ_2HZ;
+      lastboot = (double) hss->seq_send_times[0].tv_sec - (hss->si.timestamps[0] / 2); 
       hss->si.lastboot = hss->seq_send_times[0].tv_sec - (hss->si.timestamps[0] / 2); 
     }
     else if (avg_ts_hz > 70 && avg_ts_hz < 150) {
       hss->si.ts_seqclass = TS_SEQ_100HZ;
-      hss->si.lastboot = hss->seq_send_times[0].tv_sec - (hss->si.timestamps[0] / 100);
+      lastboot = (double) hss->seq_send_times[0].tv_sec - (hss->si.timestamps[0] / 100);
     }
     else if (avg_ts_hz > 724 && avg_ts_hz < 1448) {
       hss->si.ts_seqclass = TS_SEQ_1000HZ;
-      hss->si.lastboot = hss->seq_send_times[0].tv_sec - (hss->si.timestamps[0] / 1000); 
+      lastboot = (double) hss->seq_send_times[0].tv_sec - (hss->si.timestamps[0] / 1000); 
     }
     else if (avg_ts_hz > 0) {
       hss->si.ts_seqclass = TS_SEQ_OTHER_NUM;
-      hss->si.lastboot = hss->seq_send_times[0].tv_sec - (hss->si.timestamps[0] / (unsigned int)(0.5 + avg_ts_hz));
+      lastboot = (double) hss->seq_send_times[0].tv_sec - (hss->si.timestamps[0] / (unsigned int)(0.5 + avg_ts_hz));
     }
     
-    if (hss->si.lastboot && (hss->seq_send_times[0].tv_sec - hss->si.lastboot > 63072000)) {
+    if (lastboot != 0.0 && (hss->seq_send_times[0].tv_sec - lastboot > 63072000)) {
       /* Up 2 years?  Perhaps, but they're probably lying. */
       if (o.debugging) {
         log_write(LOG_STDOUT, "Ignoring claimed %s uptime of %lu days", 
 	      hss->target->targetipstr(),
               (hss->seq_send_times[0].tv_sec - hss->si.lastboot) / 86400);
       }
-      hss->si.lastboot = 0;
+      lastboot = 0;
     }
+    hss->si.lastboot = lastboot;
   }
 
   switch(hss->si.ts_seqclass) {