diff --git a/hw/application_fpga/fw/tk1/main.c b/hw/application_fpga/fw/tk1/main.c
index d6a460a..ac96a14 100644
--- a/hw/application_fpga/fw/tk1/main.c
+++ b/hw/application_fpga/fw/tk1/main.c
@@ -158,6 +158,7 @@ static void compute_cdi(const uint8_t *digest, const uint8_t use_uss,
 static void copy_name(uint8_t *buf, const size_t bufsiz, const uint32_t word)
 {
 	assert(bufsiz >= 4);
+	assert(buf != NULL);
 
 	buf[0] = word >> 24;
 	buf[1] = word >> 16;