diff --git a/src/lib/rc/dsm.c b/src/lib/rc/dsm.c
index e85cb5ba85..018f5c6272 100644
--- a/src/lib/rc/dsm.c
+++ b/src/lib/rc/dsm.c
@@ -594,7 +594,7 @@ dsm_input(int fd, uint16_t *values, uint16_t *num_values, bool *dsm_11_bit, uint
 }
 
 bool
-dsm_parse(uint64_t now, uint8_t *frame, unsigned len, uint16_t *values,
+dsm_parse(const uint64_t now, const uint8_t *frame, const unsigned len, uint16_t *values,
 	  uint16_t *num_values, bool *dsm_11_bit, unsigned *frame_drops, uint16_t max_channels)
 {
 
@@ -691,10 +691,7 @@ dsm_parse(uint64_t now, uint8_t *frame, unsigned len, uint16_t *values,
 	}
 
 	if (decode_ret) {
-		/* num values should not decrease, only increase */
-		if (dsm_chan_count > *num_values) {
-			*num_values = dsm_chan_count;
-		}
+		*num_values = dsm_chan_count;
 
 		memcpy(&values[0], &dsm_chan_buf[0], dsm_chan_count * sizeof(dsm_chan_buf[0]));
 #ifdef DSM_DEBUG
diff --git a/src/lib/rc/dsm.h b/src/lib/rc/dsm.h
index e42897e407..fb9e70f16d 100644
--- a/src/lib/rc/dsm.h
+++ b/src/lib/rc/dsm.h
@@ -60,7 +60,7 @@ __EXPORT int	dsm_config(int dsm_fd);
 __EXPORT bool	dsm_input(int dsm_fd, uint16_t *values, uint16_t *num_values, bool *dsm_11_bit, uint8_t *n_bytes,
 			  uint8_t **bytes, unsigned max_values);
 
-__EXPORT bool	dsm_parse(uint64_t now, uint8_t *frame, unsigned len, uint16_t *values,
+__EXPORT bool	dsm_parse(const uint64_t now, const uint8_t *frame, const unsigned len, uint16_t *values,
 			  uint16_t *num_values, bool *dsm_11_bit, unsigned *frame_drops, uint16_t max_channels);
 
 #ifdef GPIO_SPEKTRUM_PWR_EN
diff --git a/src/lib/rc/rc_tests/RCTest.cpp b/src/lib/rc/rc_tests/RCTest.cpp
index 5a35f3cc30..216dd14d92 100644
--- a/src/lib/rc/rc_tests/RCTest.cpp
+++ b/src/lib/rc/rc_tests/RCTest.cpp
@@ -103,7 +103,7 @@ bool RCTest::dsmTest(const char *filepath, unsigned expected_chancount, unsigned
 					&dsm_11_bit, &dsm_frame_drops, max_channels);
 
 		if (result) {
-			ut_test(num_values == expected_chancount);
+			ut_compare("num_values == expected_chancount", num_values, expected_chancount);
 
 			ut_test(abs((int)chan0 - (int)rc_values[0]) < 30);