diff --git a/SDBlockDevice.cpp b/SDBlockDevice.cpp
index 2801007fb9..2cf40984c0 100644
--- a/SDBlockDevice.cpp
+++ b/SDBlockDevice.cpp
@@ -145,6 +145,7 @@
 
 #include "SDBlockDevice.h"
 #include "mbed_debug.h"
+#include <errno.h>
 
 #define SD_COMMAND_TIMEOUT                       5000   /*!< Timeout in ms for response */
 #define SD_CMD0_GO_IDLE_STATE_RETRIES            5      /*!< Number of retries for sending CMDO */
@@ -352,7 +353,12 @@ int SDBlockDevice::init()
     }
 
     // Set SCK for data transfer
-    _freq();
+    err = _freq();
+    if (err) {
+        _lock.unlock();
+        return err;
+    }
+
     _lock.unlock();
     return BD_ERROR_OK;
 }
@@ -593,9 +599,9 @@ int SDBlockDevice::frequency(uint64_t freq)
 {
     _lock.lock();
     _transfer_sck = freq;
-    _freq();
+    int err = _freq();
     _lock.unlock();
-    return 0;
+    return err;
 }
 
 // PRIVATE FUNCTIONS
@@ -604,12 +610,12 @@ int SDBlockDevice::_freq(void)
     // Max frequency supported is 25MHZ
     if (_transfer_sck <= 25000000) {
         _spi.frequency(_transfer_sck);
-    }
-    else {  // TODO: Switch function to be implemented for higher frequency
+        return 0;
+    } else {  // TODO: Switch function to be implemented for higher frequency
         _transfer_sck = 25000000;
         _spi.frequency(_transfer_sck);
+        return -EINVAL;
     }
-    return 0;
 }
 
 uint8_t SDBlockDevice::_cmd_spi(SDBlockDevice::cmdSupported cmd, uint32_t arg) {