diff --git a/sys/fido2/Makefile.dep b/sys/fido2/Makefile.dep
index 7830b7e6f3..9f447ef7e1 100644
--- a/sys/fido2/Makefile.dep
+++ b/sys/fido2/Makefile.dep
@@ -28,4 +28,5 @@ endif
   USEMODULE += crypto_aes_256
   USEMODULE += hashes
   USEMODULE += fido2
+  USEMODULE += fmt
 endif
diff --git a/sys/fido2/ctap/ctap.c b/sys/fido2/ctap/ctap.c
index f64c118ef3..55a61b8eff 100644
--- a/sys/fido2/ctap/ctap.c
+++ b/sys/fido2/ctap/ctap.c
@@ -921,7 +921,6 @@ static int _get_key_agreement(void)
     int ret;
     ctap_public_key_cose_t key = { 0 };
 
-
     /* generate key agreement key */
     ret =
         fido2_ctap_crypto_gen_keypair(&_state.ag_key.pub, _state.ag_key.priv,
diff --git a/sys/fido2/ctap/ctap_cbor.c b/sys/fido2/ctap/ctap_cbor.c
index 540889e300..b1b5b223aa 100644
--- a/sys/fido2/ctap/ctap_cbor.c
+++ b/sys/fido2/ctap/ctap_cbor.c
@@ -107,14 +107,16 @@ static ctap_status_code_t _parse_int(CborValue *it, int *num);
 /**
  * @brief Parse credential description
  */
-static ctap_status_code_t _fido2_ctap_cbor_parse_cred_desc(CborValue *arr, ctap_cred_desc_alt_t *cred);
+static ctap_status_code_t _fido2_ctap_cbor_parse_cred_desc(CborValue *arr,
+                                                           ctap_cred_desc_alt_t *cred);
 
 /**
  * @brief Encode public key into COSE_KEY format
  *
  * See https://tools.ietf.org/html/rfc8152#page-34 Section 13.1.1 for details.
  */
-static ctap_status_code_t _encode_public_key_cose(CborEncoder *cose_key, const ctap_public_key_cose_t *key);
+static ctap_status_code_t _encode_public_key_cose(CborEncoder *cose_key,
+                                                  const ctap_public_key_cose_t *key);
 
 /**
  * @brief Encode PublicKeyCredentialDescriptor into CBOR format
@@ -743,7 +745,8 @@ static ctap_status_code_t _encode_user_entity(CborEncoder *encoder,
     return CTAP2_OK;
 }
 
-static ctap_status_code_t _encode_public_key_cose(CborEncoder *cose_key, const ctap_public_key_cose_t *key)
+static ctap_status_code_t _encode_public_key_cose(CborEncoder *cose_key,
+                                                  const ctap_public_key_cose_t *key)
 {
     int ret;
     CborEncoder map;
@@ -1620,7 +1623,8 @@ static ctap_status_code_t _parse_exclude_list(CborValue *it, ctap_cred_desc_alt_
     return CTAP2_OK;
 }
 
-static ctap_status_code_t _fido2_ctap_cbor_parse_cred_desc(CborValue *arr, ctap_cred_desc_alt_t *cred)
+static ctap_status_code_t _fido2_ctap_cbor_parse_cred_desc(CborValue *arr,
+                                                           ctap_cred_desc_alt_t *cred)
 {
     int ret;
     int type;
diff --git a/sys/fido2/ctap/ctap_crypto.c b/sys/fido2/ctap/ctap_crypto.c
index 81cd9fdd94..0dba6eb76a 100644
--- a/sys/fido2/ctap/ctap_crypto.c
+++ b/sys/fido2/ctap/ctap_crypto.c
@@ -44,8 +44,6 @@ static ctap_status_code_t _sig_to_der_format(uint8_t *r, uint8_t *s, uint8_t *si
  *
  * wrapper for @ref fido2_ctap_crypto_prng
  */
-static int _RNG(uint8_t *dest, unsigned size);
-
 static int _RNG(uint8_t *dest, unsigned size)
 {
     fido2_ctap_crypto_prng(dest, (size_t)size);
@@ -71,7 +69,8 @@ ctap_status_code_t fido2_ctap_crypto_sha256_init(sha256_context_t *ctx)
     return CTAP2_OK;
 }
 
-ctap_status_code_t fido2_ctap_crypto_sha256_update(sha256_context_t *ctx, const void *data, size_t len)
+ctap_status_code_t fido2_ctap_crypto_sha256_update(sha256_context_t *ctx,
+                                                   const void *data, size_t len)
 {
     sha256_update(ctx, data, len);
     return CTAP2_OK;
@@ -97,7 +96,8 @@ ctap_status_code_t fido2_ctap_crypto_hmac_sha256_init(hmac_context_t *ctx, const
     return CTAP2_OK;
 }
 
-ctap_status_code_t fido2_ctap_crypto_hmac_sha256_update(hmac_context_t *ctx, const void *data, size_t len)
+ctap_status_code_t fido2_ctap_crypto_hmac_sha256_update(hmac_context_t *ctx,
+                                                        const void *data, size_t len)
 {
     hmac_sha256_update(ctx, data, len);
     return CTAP2_OK;
diff --git a/sys/fido2/ctap/ctap_mem.c b/sys/fido2/ctap/ctap_mem.c
index cb4a00028a..629f7a669d 100644
--- a/sys/fido2/ctap/ctap_mem.c
+++ b/sys/fido2/ctap/ctap_mem.c
@@ -30,7 +30,7 @@
 
 #ifdef BOARD_NATIVE
 #include "mtd_default.h"
-// native mtd is file backed => Start address of flash is 0.
+/* native mtd is file backed => Start address of flash is 0. */
 char *_backing_memory = NULL;
 static mtd_dev_t *_mtd_dev = NULL;
 #else
diff --git a/tests/sys/fido2_ctap/Makefile b/tests/sys/fido2_ctap/Makefile
index 66a265adb2..9fd89cdf42 100644
--- a/tests/sys/fido2_ctap/Makefile
+++ b/tests/sys/fido2_ctap/Makefile
@@ -1,4 +1,11 @@
-include ../Makefile.tests_common
+BOARD ?= native
+
+include ../Makefile.sys_common
+
+BOARD_WHITELIST = \
+  native \
+  nrf52840dk \
+  nrf52840dongle
 
 # same as CTAP_STACKSIZE
 CFLAGS += -DTHREAD_STACKSIZE_MAIN=15000
diff --git a/tests/sys/fido2_ctap_hid/Makefile b/tests/sys/fido2_ctap_hid/Makefile
index 51b1153a93..0b26274ee7 100644
--- a/tests/sys/fido2_ctap_hid/Makefile
+++ b/tests/sys/fido2_ctap_hid/Makefile
@@ -1,7 +1,11 @@
 BOARD ?= nrf52840dk
 #BOARD ?= nrf52840dongle
 
-include ../Makefile.tests_common
+include ../Makefile.sys_common
+
+BOARD_WHITELIST = \
+  nrf52840dk \
+  nrf52840dongle
 
 USEMODULE += fido2_ctap_transport_hid
 USEPKG += fido2_tests
diff --git a/tests/sys/fido2_ctap_hid/main.c b/tests/sys/fido2_ctap_hid/main.c
index 4e09323388..95a30713eb 100644
--- a/tests/sys/fido2_ctap_hid/main.c
+++ b/tests/sys/fido2_ctap_hid/main.c
@@ -19,13 +19,13 @@
 #define ENABLE_DEBUG    (0)
 #include "debug.h"
 
-#include "xtimer.h"
+#include "ztimer.h"
 
 #include "fido2/ctap/transport/ctap_transport.h"
 
 int main(void)
 {
     /* sleep in order to see early DEBUG outputs */
-    xtimer_sleep(3);
+    ztimer_sleep(ZTIMER_MSEC, 3000);
     fido2_ctap_transport_init();
 }