diff --git a/libraries/AP_Radio/AP_Radio_cc2500.cpp b/libraries/AP_Radio/AP_Radio_cc2500.cpp
index ef77124842..c2f45548ce 100644
--- a/libraries/AP_Radio/AP_Radio_cc2500.cpp
+++ b/libraries/AP_Radio/AP_Radio_cc2500.cpp
@@ -153,7 +153,7 @@ uint8_t AP_Radio_cc2500::num_channels(void)
         t_status.pps = stats.recv_packets - last_stats.recv_packets;
         last_stats = stats;
         if (lost != 0 || timeouts != 0) {
-            Debug(3,"lost=%u timeouts=%u TS=%u\n", lost, timeouts, sizeof(struct telem_packet_cc2500));
+            Debug(3,"lost=%u timeouts=%u TS=%u\n", unsigned(lost), unsigned(timeouts), sizeof(struct telem_packet_cc2500));
         }
         lost=0;
         timeouts=0;
@@ -341,7 +341,7 @@ void AP_Radio_cc2500::handle_data_packet(mavlink_channel_t chan, const mavlink_d
 {
     uint32_t ofs=0;
     memcpy(&ofs, &m.data[0], 4);
-    Debug(4, "got data96 of len %u from chan %u at offset %u\n", m.len, chan, ofs);
+    Debug(4, "got data96 of len %u from chan %u at offset %u\n", m.len, chan, unsigned(ofs));
     if (sem->take_nonblocking()) {
         fwupload.chan = chan;
         fwupload.need_ack = false;
@@ -463,7 +463,7 @@ bool AP_Radio_cc2500::handle_SRT_packet(const uint8_t *packet)
     case PKTYPE_FW_ACK: {
             // got an fw upload ack 
             Debug(4, "ack %u seq=%u acked=%u length=%u len=%u\n",
-                  data, fwupload.sequence, fwupload.acked, fwupload.length, fwupload.len);
+                  data, fwupload.sequence, unsigned(fwupload.acked), unsigned(fwupload.length), fwupload.len);
             if (fwupload.sequence == data && sem->take_nonblocking()) {
                 fwupload.sequence++;
                 fwupload.acked += fwupload.len;
@@ -666,7 +666,7 @@ void AP_Radio_cc2500::irq_timeout(void)
         uint32_t now = AP_HAL::micros();
         
         if (now - packet_timer > 50*sync_time_us) {
-            Debug(3,"searching %u\n", now - packet_timer);
+            Debug(3,"searching %u\n", unsigned(now - packet_timer));
             cc2500.Strobe(CC2500_SIDLE);
             cc2500.Strobe(CC2500_SFRX);
             nextChannel(1);
diff --git a/libraries/AP_Radio/AP_Radio_cypress.cpp b/libraries/AP_Radio/AP_Radio_cypress.cpp
index e95c50944f..20f64b265c 100644
--- a/libraries/AP_Radio/AP_Radio_cypress.cpp
+++ b/libraries/AP_Radio/AP_Radio_cypress.cpp
@@ -356,13 +356,13 @@ void AP_Radio_cypress::update(void)
 void AP_Radio_cypress::print_debug_info(void)
 {
     Debug(2, "recv:%3u bad:%3u to:%3u re:%u N:%2u TXI:%u TX:%u 1:%4u 2:%4u 3:%4u 4:%4u 5:%4u 6:%4u 7:%4u 8:%4u 14:%u\n",
-          stats.recv_packets - last_stats.recv_packets,
-          stats.bad_packets - last_stats.bad_packets,
-          stats.timeouts - last_stats.timeouts,
-          stats.recv_errors - last_stats.recv_errors,
+          unsigned(stats.recv_packets - last_stats.recv_packets),
+          unsigned(stats.bad_packets - last_stats.bad_packets),
+          unsigned(stats.timeouts - last_stats.timeouts),
+          unsigned(stats.recv_errors - last_stats.recv_errors),
           num_channels(),
-          dsm.send_irq_count,
-          dsm.send_count,
+          unsigned(dsm.send_irq_count),
+          unsigned(dsm.send_count),
           dsm.pwm_channels[0], dsm.pwm_channels[1], dsm.pwm_channels[2], dsm.pwm_channels[3], 
           dsm.pwm_channels[4], dsm.pwm_channels[5], dsm.pwm_channels[6], dsm.pwm_channels[7],
           dsm.pwm_channels[13]);
@@ -807,7 +807,7 @@ bool AP_Radio_cypress::parse_dsm_channels(const uint8_t *data)
         if (chan == 7 && key == 0) {
             // got an ack from key 0
             Debug(4, "ack %u seq=%u acked=%u length=%u len=%u\n",
-                  v, fwupload.sequence, fwupload.acked, fwupload.length, fwupload.len);
+                  v, fwupload.sequence, unsigned(fwupload.acked), unsigned(fwupload.length), fwupload.len);
             if (fwupload.sequence == v && sem->take_nonblocking()) {
                 fwupload.sequence++;
                 fwupload.acked += fwupload.len;
@@ -1404,7 +1404,7 @@ void AP_Radio_cypress::dsm_choose_channel(void)
 
         state = STATE_AUTOBIND;
         
-        Debug(3,"recv autobind %u\n", now - dsm.last_autobind_send);
+        Debug(3,"recv autobind %u\n", unsigned(now - dsm.last_autobind_send));
         dsm.last_autobind_send = now;
         return;
     }
@@ -1701,7 +1701,7 @@ void AP_Radio_cypress::handle_data_packet(mavlink_channel_t chan, const mavlink_
 {
     uint32_t ofs=0;
     memcpy(&ofs, &m.data[0], 4);
-    Debug(4, "got data96 of len %u from chan %u at offset %u\n", m.len, chan, ofs);
+    Debug(4, "got data96 of len %u from chan %u at offset %u\n", m.len, chan, unsigned(ofs));
     if (sem->take_nonblocking()) {
         fwupload.chan = chan;
         fwupload.need_ack = false;