diff --git a/legacy/firmware/config.c b/legacy/firmware/config.c
index 448bc1f03..19a5be3fa 100644
--- a/legacy/firmware/config.c
+++ b/legacy/firmware/config.c
@@ -422,7 +422,7 @@ void config_init(void) {
     storage_set(KEY_UUID, config_uuid, sizeof(config_uuid));
     storage_set(KEY_VERSION, &CONFIG_VERSION, sizeof(CONFIG_VERSION));
   }
-  data2hex(config_uuid, sizeof(config_uuid), config_uuid_str);
+  data2hex((const uint8_t *)config_uuid, sizeof(config_uuid), config_uuid_str);
 
   session_clear(false);
 
@@ -986,7 +986,7 @@ void config_wipe(void) {
   }
   usbTiny(oldTiny);
   random_buffer((uint8_t *)config_uuid, sizeof(config_uuid));
-  data2hex(config_uuid, sizeof(config_uuid), config_uuid_str);
+  data2hex((const uint8_t *)config_uuid, sizeof(config_uuid), config_uuid_str);
   autoLockDelayMsCached = secfalse;
   storage_set(KEY_UUID, config_uuid, sizeof(config_uuid));
   storage_set(KEY_VERSION, &CONFIG_VERSION, sizeof(CONFIG_VERSION));
diff --git a/legacy/util.c b/legacy/util.c
index b0b94c804..8b1a0ab30 100644
--- a/legacy/util.c
+++ b/legacy/util.c
@@ -32,11 +32,10 @@ void uint32hex(uint32_t num, char *str) {
 }
 
 // converts data to hexa
-void data2hex(const void *data, uint32_t len, char *str) {
-  const uint8_t *cdata = (uint8_t *)data;
+void data2hex(const uint8_t *data, uint32_t len, char *str) {
   for (uint32_t i = 0; i < len; i++) {
-    str[i * 2] = hexdigits[(cdata[i] >> 4) & 0xF];
-    str[i * 2 + 1] = hexdigits[cdata[i] & 0xF];
+    str[i * 2] = hexdigits[(data[i] >> 4) & 0xF];
+    str[i * 2 + 1] = hexdigits[data[i] & 0xF];
   }
   str[len * 2] = 0;
 }
diff --git a/legacy/util.h b/legacy/util.h
index 593dc8ff1..9ecb05936 100644
--- a/legacy/util.h
+++ b/legacy/util.h
@@ -56,7 +56,7 @@ void delay(uint32_t wait);
 void uint32hex(uint32_t num, char *str);
 
 // converts data to hexa
-void data2hex(const void *data, uint32_t len, char *str);
+void data2hex(const uint8_t *data, uint32_t len, char *str);
 
 // defined in startup.s (or setup.c for emulator)
 extern void __attribute__((noreturn)) shutdown(void);