diff --git a/module_usb_audio/endpoint0/audiorequests.xc b/module_usb_audio/endpoint0/audiorequests.xc
index 9298380f..b98a4c6f 100644
--- a/module_usb_audio/endpoint0/audiorequests.xc
+++ b/module_usb_audio/endpoint0/audiorequests.xc
@@ -46,7 +46,7 @@ extern unsigned char mixSel[MAX_MIX_COUNT][MIX_INPUTS];
 /* Global var for current frequency, set to default freq */
 unsigned int g_curSamFreq = DEFAULT_FREQ;
 unsigned int g_curSamFreq48000Family = DEFAULT_FREQ % 48000 == 0;
-unsigned int g_curSamFreqMultiplier = DEFAULT_FREQ / (DEFAULT_MCLK_FREQ / 512);
+unsigned int g_curSamFreqMultiplier = (DEFAULT_FREQ * 512 * 4) / (DEFAULT_MCLK_FREQ);
 
 /* Store an int into a char array: Note this allows non-word aligned access unlike reinerpret cast */
 static void storeInt(unsigned char buffer[], int index, int val)
diff --git a/module_usb_audio/usb_buffer/usb_buffer.xc b/module_usb_audio/usb_buffer/usb_buffer.xc
index 0c607308..4827f616 100644
--- a/module_usb_audio/usb_buffer/usb_buffer.xc
+++ b/module_usb_audio/usb_buffer/usb_buffer.xc
@@ -161,7 +161,7 @@ void buffer(register chanend c_aud_out, register chanend c_aud_in,
 #endif
     unsigned u_tmp;
     unsigned sampleFreq = 0;
-    unsigned lastClock;
+    unsigned lastClock = 0;
 
     unsigned clocks = 0;
 
@@ -410,7 +410,7 @@ void buffer(register chanend c_aud_out, register chanend c_aud_in,
                     /* Number of MCLKS this SOF, approx 125 * 24 (3000), sample by sample rate */
                     GET_SHARED_GLOBAL(cycles, g_curSamFreqMultiplier);
                     cycles = ((int)((short)(u_tmp - lastClock))) * cycles;
-                    cycles >>= 2; /* /4 */ 
+                    cycles = (int) cycles >> 2; /* /4 */ 
 
                     /* Any odd bits (lower than 16.23) have to be kept seperate */
                     remnant += cycles & mask;