diff --git a/src/fsk.c b/src/fsk.c
index d782238..bdeca61 100644
--- a/src/fsk.c
+++ b/src/fsk.c
@@ -438,7 +438,7 @@ fsk_frame_analyze( fsk_plan *fskp, float *samples, float samples_per_bit,
     // into the bits_outp word.
     *bits_outp = 0;
     for ( bitnum=0; bitnum<n_bits; bitnum++ )
-	*bits_outp |= bit_values[bitnum] << bitnum;
+	*bits_outp |= (unsigned long long) bit_values[bitnum] << bitnum;
 
     debug_log("    frame algo=%u confidence=%f ampl=%f\n",
 	    CONFIDENCE_ALGO, confidence, *ampl_outp);
@@ -455,7 +455,7 @@ fsk_find_frame( fsk_plan *fskp, float *samples, unsigned int frame_nsamples,
 	const char *expect_bits_string,
 	unsigned long long *bits_outp,
 	float *ampl_outp,
-	unsigned long long *frame_start_outp
+	unsigned int *frame_start_outp
 	)
 {
     int expect_n_bits = strlen(expect_bits_string);
@@ -466,7 +466,7 @@ fsk_find_frame( fsk_plan *fskp, float *samples, unsigned int frame_nsamples,
 
     unsigned int best_t = 0;
     float best_c = 0.0, best_a = 0.0;
-    unsigned int best_bits = 0;
+    unsigned long long best_bits = 0;
     
     // Scan the frame positions starting with the one try_first_sample,
     // alternating between a step above that, a step below that, above, below,
diff --git a/src/fsk.h b/src/fsk.h
index 37e7d0e..616c871 100644
--- a/src/fsk.h
+++ b/src/fsk.h
@@ -67,7 +67,7 @@ fsk_find_frame( fsk_plan *fskp, float *samples, unsigned int frame_nsamples,
 	const char *expect_bits_string,
 	unsigned long long *bits_outp,
 	float *ampl_outp,
-	unsigned long long *frame_start_outp
+	unsigned int *frame_start_outp
 	);
 
 int
diff --git a/src/minimodem.c b/src/minimodem.c
index 48f4e62..d80ed50 100644
--- a/src/minimodem.c
+++ b/src/minimodem.c
@@ -1089,7 +1089,7 @@ main( int argc, char*argv[] )
 	unsigned long long bits = 0;
 	/* Note: frame_start_sample is actually the sample where the
 	 * prev_stop bit begins (since the "frame" includes the prev_stop). */
-	unsigned long long frame_start_sample = 0;
+	unsigned int frame_start_sample = 0;
 
 	unsigned int try_first_sample;
 	float try_confidence_search_limit;
@@ -1204,7 +1204,7 @@ main( int argc, char*argv[] )
 		try_confidence_search_limit = INFINITY;
 		float confidence2, amplitude2;
 		unsigned long long bits2;
-		unsigned long long frame_start_sample2;
+		unsigned int frame_start_sample2;
 		confidence2 = fsk_find_frame(fskp, samplebuf, expect_nsamples,
 			    try_first_sample,
 			    try_max_nsamples,
@@ -1258,7 +1258,8 @@ main( int argc, char*argv[] )
 
 	// chop off framing bits
 	unsigned int frame_bits_shift = bfsk_nstartbits;
-	unsigned int frame_bits_mask = (int)(1<<bfsk_n_data_bits) - 1;
+	unsigned long long frame_bits_mask = (long long)(1ULL<<bfsk_n_data_bits) - 1;
+	debug_log("Input: %08x%08x - Databits: %i - Shift: %i - Mask: %08x\n", (unsigned int)(bits >> 32), (unsigned int)bits, bfsk_n_data_bits, bfsk_nstartbits, (unsigned int)(frame_bits_mask >> 32), (unsigned int)(frame_bits_mask));
 	bits = ( bits >> frame_bits_shift ) & frame_bits_mask;
 
 	unsigned int dataout_size = 4096;