Index: tools/debugserver/source/RNBRemote.h
===================================================================
--- tools/debugserver/source/RNBRemote.h
+++ tools/debugserver/source/RNBRemote.h
@@ -154,7 +154,7 @@
 
     nub_thread_t    GetCurrentThread () const
                     {
-                        if (m_thread == 0 || m_thread == -1)
+                        if (m_thread == 0 || m_thread == static_cast<nub_thread_t>(-1))
                             return DNBProcessGetCurrentThread (m_ctx.ProcessID());
                         return m_thread;
                     }
Index: tools/debugserver/source/RNBRemote.cpp
===================================================================
--- tools/debugserver/source/RNBRemote.cpp
+++ tools/debugserver/source/RNBRemote.cpp
@@ -322,7 +322,7 @@
     }
     else
     {
-        for (int i = 0; i != s.size(); ++i)
+        for (size_t i = 0; i != s.size(); ++i)
             cksum += s[i];
         snprintf (hexbuf, sizeof hexbuf, "%02x", cksum & 0xff);
         sendpacket += hexbuf;
@@ -398,7 +398,7 @@
             int packet_checksum = 0;
             if (!m_noack_mode)
             {
-                for (int i = return_packet.size() - 2; i < return_packet.size(); ++i)
+                for (size_t i = return_packet.size() - 2; i < return_packet.size(); ++i)
                 {
                     char checksum_char = tolower (return_packet[i]);
                     if (!isxdigit (checksum_char))
@@ -788,14 +788,14 @@
                 case rnb_success:
                     break;
 
-                default:
-                case rnb_err:
-                    DNBLogThreadedIf (LOG_RNB_REMOTE, "RNBSocket::GetCommData returned error %u", err);
+                case rnb_not_connected:
+                    DNBLogThreadedIf (LOG_RNB_REMOTE, "RNBSocket::GetCommData returned not connected...");
                     done = true;
                     break;
 
-                case rnb_not_connected:
-                    DNBLogThreadedIf (LOG_RNB_REMOTE, "RNBSocket::GetCommData returned not connected...");
+                case rnb_err:
+                default:
+                    DNBLogThreadedIf (LOG_RNB_REMOTE, "RNBSocket::GetCommData returned error %u", err);
                     done = true;
                     break;
             }
@@ -856,7 +856,7 @@
     {
         return bytes;
     }
-    if (len == -1)
+    if (len == static_cast<size_t>(-1))
         len = strlen (str);
 
     while (len--)
@@ -2214,15 +2214,14 @@
 void
 append_hex_value (std::ostream& ostrm, const uint8_t* buf, size_t buf_size, bool swap)
 {
-    int i;
     if (swap)
     {
-        for (i = buf_size-1; i >= 0; i--)
+        for (long i = buf_size-1; i >= 0; i--)
             ostrm << RAWHEX8(buf[i]);
     }
     else
     {
-        for (i = 0; i < buf_size; i++)
+        for (size_t i = 0; i < buf_size; i++)
             ostrm << RAWHEX8(buf[i]);
     }
 }
@@ -2353,7 +2352,7 @@
                 // the thread name contains special chars, send as hex bytes
                 ostrm << std::hex << "hexname:";
                 uint8_t *u_thread_name = (uint8_t *)thread_name;
-                for (int i = 0; i < thread_name_len; i++)
+                for (size_t i = 0; i < thread_name_len; i++)
                     ostrm << RAWHEX8(u_thread_name[i]);
                 ostrm << ';';
             }
@@ -2421,7 +2420,7 @@
         {
             ostrm << "metype:" << std::hex << tid_stop_info.details.exception.type << ";";
             ostrm << "mecount:" << std::hex << tid_stop_info.details.exception.data_count << ";";
-            for (int i = 0; i < tid_stop_info.details.exception.data_count; ++i)
+            for (nub_size_t i = 0; i < tid_stop_info.details.exception.data_count; ++i)
                 ostrm << "medata:" << std::hex << tid_stop_info.details.exception.data[i] << ";";
         }
         return SendPacket (ostrm.str ());
@@ -2645,7 +2644,7 @@
     length = bytes_read;
 
     std::ostringstream ostrm;
-    for (int i = 0; i < length; i++)
+    for (uint32_t i = 0; i < length; i++)
         ostrm << RAWHEX8(buf[i]);
     return SendPacket (ostrm.str ());
 }
@@ -2686,7 +2685,7 @@
     p += (c - p) + 1;
 
     errno = 0;
-    int length = strtoul (p, NULL, 16);
+    unsigned length = strtoul (p, NULL, 16);
     if (errno != 0)
     {
         return HandlePacket_ILLFORMED (__FILE__, __LINE__, p, "Invalid length in x packet");
@@ -2727,7 +2726,7 @@
     length = buf_quoted.size();
 
     std::ostringstream ostrm;
-    for (int i = 0; i < length; i++)
+    for (unsigned i = 0; i < length; i++)
         ostrm << buf_quoted[i];
 
     return SendPacket (ostrm.str ());
@@ -3495,7 +3494,7 @@
         DNBLogError("RNBRemote::HandlePacket_p(%s): unknown register number %u requested\n", p, reg);
         ostrm << "00000000";
     }
-    else if (reg_entry->nub_info.reg == -1)
+    else if (reg_entry->nub_info.reg == static_cast<uint32_t>(-1))
     {
         if (reg_entry->nub_info.size > 0)
         {
@@ -3554,7 +3553,8 @@
 
     reg_entry = &g_reg_entries[reg];
 
-    if (reg_entry->nub_info.set == -1 && reg_entry->nub_info.reg == -1)
+    if (reg_entry->nub_info.set == static_cast<uint32_t>(-1) &&
+        reg_entry->nub_info.reg == static_cast<uint32_t>(-1))
     {
         DNBLogError("RNBRemote::HandlePacket_P(%s): unknown register number %u requested\n", p, reg);
         return SendPacket("E48");
@@ -3911,7 +3911,7 @@
 
     // Hardware supported stepping not supported on arm
     nub_thread_t tid = GetContinueThread ();
-    if (tid == 0 || tid == -1)
+    if (tid == 0 || tid == static_cast<nub_thread_t>(-1))
         tid = GetCurrentThread();
 
     if (tid == INVALID_NUB_THREAD)
@@ -3959,7 +3959,7 @@
     }
 
     action.tid = GetContinueThread ();
-    if (action.tid == 0 || action.tid == -1)
+    if (action.tid == 0 || action.tid == static_cast<nub_thread_t>(-1))
         return SendPacket ("E40");
 
     nub_state_t tstate = DNBThreadGetState (pid, action.tid);