diff --git a/lib/include/srslte/phy/utils/bit.h b/lib/include/srslte/phy/utils/bit.h
index 6c34a1552..2ec697912 100644
--- a/lib/include/srslte/phy/utils/bit.h
+++ b/lib/include/srslte/phy/utils/bit.h
@@ -69,7 +69,7 @@ SRSLTE_API void srslte_bit_interleave_w_offset(uint8_t*  input,
                                                uint32_t  nof_bits,
                                                uint32_t  w_offset);
 
-SRSLTE_API void srslte_bit_unpack_vector(uint8_t* packed, uint8_t* unpacked, int nof_bits);
+SRSLTE_API void srslte_bit_unpack_vector(const uint8_t* packed, uint8_t* unpacked, int nof_bits);
 
 SRSLTE_API void srslte_bit_pack_vector(uint8_t* unpacked, uint8_t* packed, int nof_bits);
 
diff --git a/lib/src/phy/utils/bit.c b/lib/src/phy/utils/bit.c
index 7a1a0d932..a8264577d 100644
--- a/lib/src/phy/utils/bit.c
+++ b/lib/src/phy/utils/bit.c
@@ -697,7 +697,7 @@ void srslte_bit_copy(uint8_t* dst, uint32_t dst_offset, uint8_t* src, uint32_t s
   }
 }
 
-void srslte_bit_unpack_vector(uint8_t* packed, uint8_t* unpacked, int nof_bits)
+void srslte_bit_unpack_vector(const uint8_t* packed, uint8_t* unpacked, int nof_bits)
 {
   uint32_t i, nbytes;
   nbytes = nof_bits / 8;