diff --git a/TNC/HdlcFrame.cpp b/TNC/HdlcFrame.cpp
index 5bfd2f1..a101a7c 100644
--- a/TNC/HdlcFrame.cpp
+++ b/TNC/HdlcFrame.cpp
@@ -3,6 +3,7 @@
 
 #include "HdlcFrame.hpp"
 #include "Log.h"
+#include "cmsis_os.h"
 
 namespace mobilinkd { namespace tnc { namespace hdlc {
 
@@ -25,4 +26,14 @@ IoFrame* acquire()
     return result;
 }
 
+
+IoFrame* acquire_wait()
+{
+    IoFrame* result = nullptr;
+    while ((result = ioFramePool().acquire()) == nullptr) {
+        osThreadYield();
+    }
+    return result;
+}
+
 }}} // mobilinkd::tnc::hdlc
diff --git a/TNC/HdlcFrame.hpp b/TNC/HdlcFrame.hpp
index aadf5a0..09fc2c7 100644
--- a/TNC/HdlcFrame.hpp
+++ b/TNC/HdlcFrame.hpp
@@ -205,6 +205,7 @@ IoFramePool& ioFramePool(void);
 void release(IoFrame* frame);
 
 IoFrame* acquire(void);
+IoFrame* acquire_wait(void);
 
 }}} // mobilinkd::tnc::hdlc
 
diff --git a/TNC/KissHardware.cpp b/TNC/KissHardware.cpp
index 330a7bd..7b00d72 100644
--- a/TNC/KissHardware.cpp
+++ b/TNC/KissHardware.cpp
@@ -235,7 +235,7 @@ void Hardware::handle_request(hdlc::IoFrame* frame) {
         output_gain = *it << 8;
         ++it;
         output_gain += *it;
-        DEBUG("SET_OUTPUT_VOLUME = %d", output_gain);
+        DEBUG("SET_OUTPUT_GAIN = %d", output_gain);
         audio::setAudioOutputLevel();
         update_crc();
         [[fallthrough]];
diff --git a/TNC/SerialPort.cpp b/TNC/SerialPort.cpp
index 6fbd2e8..30848a3 100644
--- a/TNC/SerialPort.cpp
+++ b/TNC/SerialPort.cpp
@@ -56,7 +56,7 @@ extern "C" void startSerialTask(void const* arg)
 
     State state = WAIT_FBEGIN;
 
-    hdlc::IoFrame* frame = hdlc::acquire();
+    hdlc::IoFrame* frame = hdlc::acquire_wait();
 
     HAL_UART_Receive_IT(&huart3, &rxBuffer, 1);
 
@@ -72,7 +72,7 @@ extern "C" void startSerialTask(void const* arg)
             hdlc::release(frame);
             ERROR("UART Error: %08lx", evt.value.v);
             uart_error.store(HAL_UART_ERROR_NONE);
-            frame = hdlc::acquire();
+            frame = hdlc::acquire_wait();
             HAL_UART_Receive_IT(&huart3, &rxBuffer, 1);
             continue;
         }
@@ -94,8 +94,12 @@ extern "C" void startSerialTask(void const* arg)
                 break;
             case FEND:
                 frame->source(hdlc::IoFrame::SERIAL_DATA);
-                osMessagePut(ioEventQueueHandle, reinterpret_cast<uint32_t>(frame), osWaitForever);
-                frame = hdlc::acquire();
+                if (osMessagePut(ioEventQueueHandle, reinterpret_cast<uint32_t>(frame), osWaitForever) != osOK)
+                {
+                    hdlc::release(frame);
+                }
+                osDelay(10);
+                frame = hdlc::acquire_wait();
                 state = WAIT_FBEGIN;
                 break;
             default:
@@ -113,7 +117,7 @@ extern "C" void startSerialTask(void const* arg)
                 if (not frame->push_back(FESC)) {
                     hdlc::release(frame);
                     state = WAIT_FBEGIN;  // Drop frame;
-                    frame = hdlc::acquire();
+                    frame = hdlc::acquire_wait();
                 }
                 break;
             case TFEND:
@@ -126,7 +130,7 @@ extern "C" void startSerialTask(void const* arg)
             default:
                 hdlc::release(frame);
                 state = WAIT_FBEGIN;  // Drop frame;
-                frame = hdlc::acquire();
+                frame = hdlc::acquire_wait();
             }
             break;
         }