diff --git a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-bip32.h b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-bip32.h
index afae08650..ed0794b59 100644
--- a/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-bip32.h
+++ b/core/embed/extmod/modtrezorcrypto/modtrezorcrypto-bip32.h
@@ -131,8 +131,10 @@ STATIC mp_obj_t mod_trezorcrypto_HDNode_make_new(const mp_obj_type_t *type,
   }
   if (33 == public_key.len) {
     memcpy(o->hdnode.public_key, public_key.buf, 33);
+    o->hdnode.is_public_key_set = true;
   } else {
     memzero(o->hdnode.public_key, 33);
+    o->hdnode.is_public_key_set = false;
   }
   o->hdnode.curve = curve;
 
diff --git a/crypto/bip32.c b/crypto/bip32.c
index 09723d9fd..741049c43 100644
--- a/crypto/bip32.c
+++ b/crypto/bip32.c
@@ -103,6 +103,7 @@ int hdnode_from_xpub(uint32_t depth, uint32_t child_num,
   memzero(out->private_key, 32);
   memzero(out->private_key_extension, 32);
   memcpy(out->public_key, public_key, 33);
+  out->is_public_key_set = true;
   return 1;
 }
 
@@ -136,6 +137,7 @@ int hdnode_from_xprv(uint32_t depth, uint32_t child_num,
   memcpy(out->chain_code, chain_code, 32);
   memcpy(out->private_key, private_key, 32);
   memzero(out->public_key, sizeof(out->public_key));
+  out->is_public_key_set = false;
   memzero(out->private_key_extension, sizeof(out->private_key_extension));
   return 1;
 }
@@ -174,6 +176,7 @@ int hdnode_from_seed(const uint8_t *seed, int seed_len, const char *curve,
   memcpy(out->private_key, I, 32);
   memcpy(out->chain_code, I + 32, 32);
   memzero(out->public_key, sizeof(out->public_key));
+  out->is_public_key_set = false;
   memzero(I, sizeof(I));
   return 1;
 }
@@ -255,6 +258,7 @@ int hdnode_private_ckd_bip32(HDNode *inout, uint32_t i) {
   inout->depth++;
   inout->child_num = i;
   memzero(inout->public_key, sizeof(inout->public_key));
+  inout->is_public_key_set = false;
 
   // making sure to wipe our memory
   memzero(&a, sizeof(a));
@@ -329,6 +333,7 @@ int hdnode_public_ckd(HDNode *inout, uint32_t i) {
   inout->child_num = i;
   inout->public_key[0] = 0x02 | (child.y.val[0] & 0x01);
   bn_write_be(&child.x, inout->public_key + 1);
+  inout->is_public_key_set = true;
 
   // Wipe all stack data.
   memzero(&parent, sizeof(parent));
@@ -468,7 +473,9 @@ int hdnode_get_address(HDNode *node, uint32_t version, char *addr,
 }
 
 int hdnode_fill_public_key(HDNode *node) {
-  if (node->public_key[0] != 0) return 0;
+  if (node->is_public_key_set) {
+    return 0;
+  }
 
 #if USE_BIP32_25519_CURVES
   if (node->curve->params) {
@@ -501,6 +508,7 @@ int hdnode_fill_public_key(HDNode *node) {
     return 1;
   }
 #endif
+  node->is_public_key_set = true;
   return 0;
 }
 
@@ -750,9 +758,11 @@ static int hdnode_deserialize(const char *str, uint32_t version,
     }
     memcpy(node->private_key, node_data + 46, 32);
     memzero(node->public_key, sizeof(node->public_key));
+    node->is_public_key_set = false;
   } else {
     memzero(node->private_key, sizeof(node->private_key));
     memcpy(node->public_key, node_data + 45, 33);
+    node->is_public_key_set = true;
   }
   node->depth = node_data[4];
   if (fingerprint) {
diff --git a/crypto/bip32.h b/crypto/bip32.h
index 4be5c4483..27084719c 100644
--- a/crypto/bip32.h
+++ b/crypto/bip32.h
@@ -56,6 +56,7 @@ typedef struct {
   uint8_t private_key_extension[32];
 
   uint8_t public_key[33];
+  bool is_public_key_set;
   const curve_info *curve;
 } HDNode;
 
diff --git a/crypto/cardano.c b/crypto/cardano.c
index 485d6514a..090dfe3ce 100644
--- a/crypto/cardano.c
+++ b/crypto/cardano.c
@@ -143,6 +143,7 @@ int hdnode_private_ckd_cardano(HDNode *inout, uint32_t index) {
   inout->depth++;
   inout->child_num = index;
   memzero(inout->public_key, sizeof(inout->public_key));
+  inout->is_public_key_set = false;
 
   // making sure to wipe our memory
   memzero(z, sizeof(z));
@@ -164,7 +165,7 @@ int hdnode_from_secret_cardano(const uint8_t secret[CARDANO_SECRET_LENGTH],
 
   cardano_ed25519_tweak_bits(out->private_key);
 
-  out->public_key[0] = 0;
+  out->is_public_key_set = false;
   if (hdnode_fill_public_key(out) != 0) {
     return 0;
   }