diff --git a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-aes.h b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-aes.h
index ab15d165a..3ef493c64 100644
--- a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-aes.h
+++ b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-aes.h
@@ -62,10 +62,8 @@ STATIC mp_obj_t mod_trezorcrypto_AES_make_new(const mp_obj_type_t *type,
                                               size_t n_args, size_t n_kw,
                                               const mp_obj_t *args) {
   mp_arg_check_num(n_args, n_kw, 2, 3, false);
-  mp_obj_AES_t *o = m_new_obj_with_finaliser(mp_obj_AES_t);
-  o->base.type = type;
-  o->mode = mp_obj_get_int(args[0]);
-  if (o->mode < ECB || o->mode > CTR) {
+  mp_int_t mode = mp_obj_get_int(args[0]);
+  if (mode < ECB || mode > CTR) {
     mp_raise_ValueError("Invalid AES mode");
   }
   mp_buffer_info_t key = {0};
@@ -74,13 +72,19 @@ STATIC mp_obj_t mod_trezorcrypto_AES_make_new(const mp_obj_type_t *type,
     mp_raise_ValueError(
         "Invalid length of key (has to be 128, 192 or 256 bits)");
   }
+  mp_buffer_info_t iv = {0};
   if (n_args > 2) {
-    mp_buffer_info_t iv = {0};
     mp_get_buffer_raise(args[2], &iv, MP_BUFFER_READ);
     if (iv.len != AES_BLOCK_SIZE) {
       mp_raise_ValueError(
           "Invalid length of initialization vector (has to be 128 bits)");
     }
+  }
+
+  mp_obj_AES_t *o = m_new_obj_with_finaliser(mp_obj_AES_t);
+  o->base.type = type;
+  o->mode = mode;
+  if (iv.len != 0) {
     memcpy(o->iv, iv.buf, AES_BLOCK_SIZE);
   } else {
     memzero(o->iv, AES_BLOCK_SIZE);
diff --git a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-blake2b.h b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-blake2b.h
index 687c5a73c..2b1f4b2f4 100644
--- a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-blake2b.h
+++ b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-blake2b.h
@@ -98,6 +98,7 @@ STATIC mp_obj_t mod_trezorcrypto_Blake2b_make_new(const mp_obj_type_t *type,
   }
 
   if (res < 0) {
+    m_del_obj(mp_obj_Blake2b_t, o);
     mp_raise_ValueError("Invalid Blake2b parameters");
   }
 
diff --git a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-blake2s.h b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-blake2s.h
index 4cf175405..3e1b28870 100644
--- a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-blake2s.h
+++ b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-blake2s.h
@@ -98,6 +98,7 @@ STATIC mp_obj_t mod_trezorcrypto_Blake2s_make_new(const mp_obj_type_t *type,
   }
 
   if (res < 0) {
+    m_del_obj(mp_obj_Blake2s_t, o);
     mp_raise_ValueError("Invalid Blake2s parameters");
   }
 
diff --git a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-cardano.h b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-cardano.h
index e3e520cf6..04caede4a 100644
--- a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-cardano.h
+++ b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-cardano.h
@@ -113,6 +113,7 @@ STATIC mp_obj_t mod_trezorcrypto_from_secret(mp_obj_t secret) {
   o->base.type = &mod_trezorcrypto_HDNode_type;
   const int res = hdnode_from_secret_cardano(bufinfo.buf, &o->hdnode);
   if (res != 1) {
+    m_del_obj(mp_obj_HDNode_t, o);
     mp_raise_msg(&mp_type_RuntimeError,
                  "Unexpected failure in constructing Cardano node.");
   }
diff --git a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-chacha20poly1305.h b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-chacha20poly1305.h
index 33a23da63..076e3ae6c 100644
--- a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-chacha20poly1305.h
+++ b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-chacha20poly1305.h
@@ -43,9 +43,6 @@ STATIC mp_obj_t mod_trezorcrypto_ChaCha20Poly1305_make_new(
     const mp_obj_type_t *type, size_t n_args, size_t n_kw,
     const mp_obj_t *args) {
   mp_arg_check_num(n_args, n_kw, 2, 2, false);
-  mp_obj_ChaCha20Poly1305_t *o =
-      m_new_obj_with_finaliser(mp_obj_ChaCha20Poly1305_t);
-  o->base.type = type;
   mp_buffer_info_t key = {0}, nonce = {0};
   mp_get_buffer_raise(args[0], &key, MP_BUFFER_READ);
   mp_get_buffer_raise(args[1], &nonce, MP_BUFFER_READ);
@@ -55,7 +52,10 @@ STATIC mp_obj_t mod_trezorcrypto_ChaCha20Poly1305_make_new(
   if (nonce.len != 12) {
     mp_raise_ValueError("Invalid length of nonce");
   }
+  mp_obj_ChaCha20Poly1305_t *o =
+      m_new_obj_with_finaliser(mp_obj_ChaCha20Poly1305_t);
   rfc7539_init(&(o->ctx), key.buf, nonce.buf);
+  o->base.type = type;
   o->alen = 0;
   o->plen = 0;
   return MP_OBJ_FROM_PTR(o);
diff --git a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-hmac.h b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-hmac.h
index 92acbebcc..c81f4f9db 100644
--- a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-hmac.h
+++ b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-hmac.h
@@ -57,8 +57,6 @@ STATIC mp_obj_t mod_trezorcrypto_Hmac_make_new(const mp_obj_type_t *type,
                                                size_t n_args, size_t n_kw,
                                                const mp_obj_t *args) {
   mp_arg_check_num(n_args, n_kw, 2, 3, false);
-  mp_obj_Hmac_t *o = m_new_obj_with_finaliser(mp_obj_Hmac_t);
-  o->base.type = type;
 
   mp_buffer_info_t key = {0};
   mp_get_buffer_raise(args[1], &key, MP_BUFFER_READ);
@@ -67,12 +65,15 @@ STATIC mp_obj_t mod_trezorcrypto_Hmac_make_new(const mp_obj_type_t *type,
     key.buf = "";
   }
 
+  mp_obj_Hmac_t *o = m_new_obj_with_finaliser(mp_obj_Hmac_t);
+  o->base.type = type;
   o->hashtype = trezor_obj_get_uint(args[0]);
   if (o->hashtype == SHA256) {
     hmac_sha256_Init(&(o->ctx256), key.buf, key.len);
   } else if (o->hashtype == SHA512) {
     hmac_sha512_Init(&(o->ctx512), key.buf, key.len);
   } else {
+    m_del_obj(mp_obj_Hmac_t, o);
     mp_raise_ValueError("Invalid hashtype");
   }
   // constructor called with message as third parameter
diff --git a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-monero.h b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-monero.h
index d7237709f..051829465 100644
--- a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-monero.h
+++ b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-monero.h
@@ -160,6 +160,7 @@ STATIC mp_obj_t mod_trezorcrypto_monero_ge25519_make_new(
   } else if (n_args == 1 && MP_OBJ_IS_STR_OR_BYTES(args[0])) {
     mp_unpack_ge25519(&o->p, args[0], 0);
   } else {
+    m_del_obj(mp_obj_ge25519_t, o);
     mp_raise_ValueError("Invalid ge25519 constructor");
   }
 
@@ -202,6 +203,7 @@ STATIC mp_obj_t mod_trezorcrypto_monero_bignum256modm_make_new(
     uint64_t v = trezor_obj_get_uint64(args[0]);
     set256_modm(o->p, v);
   } else {
+    m_del_obj(mp_obj_bignum256modm_t, o);
     mp_raise_ValueError("Invalid scalar constructor");
   }
 
diff --git a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-pbkdf2.h b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-pbkdf2.h
index 7a4245f16..1960e04b5 100644
--- a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-pbkdf2.h
+++ b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-pbkdf2.h
@@ -59,8 +59,6 @@ STATIC mp_obj_t mod_trezorcrypto_Pbkdf2_make_new(const mp_obj_type_t *type,
                                                  size_t n_args, size_t n_kw,
                                                  const mp_obj_t *args) {
   mp_arg_check_num(n_args, n_kw, 3, 4, false);
-  mp_obj_Pbkdf2_t *o = m_new_obj_with_finaliser(mp_obj_Pbkdf2_t);
-  o->base.type = type;
 
   mp_buffer_info_t password = {0};
   mp_get_buffer_raise(args[1], &password, MP_BUFFER_READ);
@@ -79,7 +77,10 @@ STATIC mp_obj_t mod_trezorcrypto_Pbkdf2_make_new(const mp_obj_type_t *type,
     blocknr = trezor_obj_get_uint(args[4]);
   }
 
-  o->prf = trezor_obj_get_uint(args[0]);
+  mp_uint_t prf = trezor_obj_get_uint(args[0]);
+  mp_obj_Pbkdf2_t *o = m_new_obj_with_finaliser(mp_obj_Pbkdf2_t);
+  o->base.type = type;
+  o->prf = prf;
   if (o->prf == PRF_HMAC_SHA256) {
     pbkdf2_hmac_sha256_Init(&(o->ctx256), password.buf, password.len, salt.buf,
                             salt.len, blocknr);
@@ -87,6 +88,7 @@ STATIC mp_obj_t mod_trezorcrypto_Pbkdf2_make_new(const mp_obj_type_t *type,
     pbkdf2_hmac_sha512_Init(&(o->ctx512), password.buf, password.len, salt.buf,
                             salt.len, blocknr);
   } else {
+    m_del_obj(mp_obj_Pbkdf2_t, o);
     mp_raise_ValueError("Invalid PRF");
   }
   // constructor called with iterations as fourth parameter
diff --git a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-sha3-256.h b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-sha3-256.h
index 3fd377005..ce9728d02 100644
--- a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-sha3-256.h
+++ b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-sha3-256.h
@@ -50,11 +50,6 @@ STATIC mp_obj_t mod_trezorcrypto_Sha3_256_make_new(const mp_obj_type_t *type,
                                                    size_t n_args, size_t n_kw,
                                                    const mp_obj_t *args) {
   mp_arg_check_num(n_args, n_kw, 0, 1, true);
-  mp_obj_Sha3_256_t *o = m_new_obj_with_finaliser(mp_obj_Sha3_256_t);
-  o->base.type = type;
-  o->keccak = 0;
-  sha3_256_Init(&(o->ctx));
-
   STATIC const mp_arg_t allowed_args[] = {
       {MP_QSTR_data, MP_ARG_OBJ, {.u_obj = mp_const_none}},
       {MP_QSTR_keccak, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = MP_OBJ_NULL}},
@@ -62,6 +57,11 @@ STATIC mp_obj_t mod_trezorcrypto_Sha3_256_make_new(const mp_obj_type_t *type,
   mp_arg_val_t vals[MP_ARRAY_SIZE(allowed_args)] = {0};
   mp_arg_parse_all_kw_array(n_args, n_kw, args, MP_ARRAY_SIZE(allowed_args),
                             allowed_args, vals);
+
+  mp_obj_Sha3_256_t *o = m_new_obj_with_finaliser(mp_obj_Sha3_256_t);
+  o->base.type = type;
+  o->keccak = 0;
+  sha3_256_Init(&(o->ctx));
   if (vals[1].u_obj != MP_OBJ_NULL) {
     o->keccak = mp_obj_is_true(vals[1].u_obj);
   }
diff --git a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-sha3-512.h b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-sha3-512.h
index 61a68ca8e..efbcadb37 100644
--- a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-sha3-512.h
+++ b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-sha3-512.h
@@ -50,11 +50,6 @@ STATIC mp_obj_t mod_trezorcrypto_Sha3_512_make_new(const mp_obj_type_t *type,
                                                    size_t n_args, size_t n_kw,
                                                    const mp_obj_t *args) {
   mp_arg_check_num(n_args, n_kw, 0, 1, true);
-  mp_obj_Sha3_512_t *o = m_new_obj_with_finaliser(mp_obj_Sha3_512_t);
-  o->base.type = type;
-  o->keccak = 0;
-  sha3_512_Init(&(o->ctx));
-
   STATIC const mp_arg_t allowed_args[] = {
       {MP_QSTR_data, MP_ARG_OBJ, {.u_obj = mp_const_none}},
       {MP_QSTR_keccak, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = MP_OBJ_NULL}},
@@ -62,6 +57,11 @@ STATIC mp_obj_t mod_trezorcrypto_Sha3_512_make_new(const mp_obj_type_t *type,
   mp_arg_val_t vals[MP_ARRAY_SIZE(allowed_args)] = {0};
   mp_arg_parse_all_kw_array(n_args, n_kw, args, MP_ARRAY_SIZE(allowed_args),
                             allowed_args, vals);
+
+  mp_obj_Sha3_512_t *o = m_new_obj_with_finaliser(mp_obj_Sha3_512_t);
+  o->base.type = type;
+  o->keccak = 0;
+  sha3_512_Init(&(o->ctx));
   if (vals[1].u_obj != MP_OBJ_NULL) {
     o->keccak = mp_obj_is_true(vals[1].u_obj);
   }