diff --git a/LibCore/CIODevice.cpp b/LibCore/CIODevice.cpp
index e393c26c02..6043011969 100644
--- a/LibCore/CIODevice.cpp
+++ b/LibCore/CIODevice.cpp
@@ -118,7 +118,7 @@ ByteBuffer CIODevice::read_line(int max_size)
         return { };
     if (m_eof) {
         if (m_buffered_data.size() > max_size) {
-            printf("CIODevice::read_line: At EOF but there's more than max_size(%d) buffered\n", max_size);
+            dbgprintf("CIODevice::read_line: At EOF but there's more than max_size(%d) buffered\n", max_size);
             return { };
         }
         auto buffer = ByteBuffer::copy(m_buffered_data.data(), m_buffered_data.size());
@@ -203,7 +203,9 @@ int CIODevice::printf(const char* format, ...)
     va_start(ap, format);
     // FIXME: We're not propagating write() failures to client here!
     int ret = printf_internal([this] (char*&, char ch) {
-        write((const byte*)&ch, 1);
+        int rc = write((const byte*)&ch, 1);
+        if (rc < 0)
+            dbgprintf("CIODevice::printf: write: %s\n", strerror(errno));
     }, nullptr, format, ap);
     va_end(ap);
     return ret;
diff --git a/LibCore/CSocket.cpp b/LibCore/CSocket.cpp
index 70f90fe88f..e29caefe29 100644
--- a/LibCore/CSocket.cpp
+++ b/LibCore/CSocket.cpp
@@ -47,15 +47,15 @@ bool CSocket::connect(const CSocketAddress& address, int port)
     m_destination_address = address;
     m_destination_port = port;
 
-    printf("Connecting to %s...", address.to_string().characters());
+    dbgprintf("Connecting to %s...", address.to_string().characters());
     fflush(stdout);
     int rc = ::connect(fd(), (struct sockaddr*)&addr, sizeof(addr));
     if (rc < 0) {
         if (errno == EINPROGRESS) {
-            printf("in progress.\n");
+            dbgprintf("in progress.\n");
             m_notifier = make<CNotifier>(fd(), CNotifier::Event::Write);
             m_notifier->on_ready_to_write = [this] {
-                printf("%s{%p} connected!\n", class_name(), this);
+                dbgprintf("%s{%p} connected!\n", class_name(), this);
                 m_connected = true;
                 m_notifier->set_event_mask(CNotifier::Event::None);
                 if (on_connected)
@@ -66,7 +66,7 @@ bool CSocket::connect(const CSocketAddress& address, int port)
         perror("connect");
         exit(1);
     }
-    printf("ok!\n");
+    dbgprintf("ok!\n");
     m_connected = true;
     return true;
 }