diff --git a/src/apdu-pubkey.c b/src/apdu-pubkey.c
index 1d1c6d9..9db0467 100644
--- a/src/apdu-pubkey.c
+++ b/src/apdu-pubkey.c
@@ -121,11 +121,11 @@ encode_xpub(
   return b58enc(b58, b58_sz, data, sizeof(data));
 }
 
-uint8_t
+uint16_t
 hns_apdu_get_public_key(
   uint8_t p1,
   uint8_t p2,
-  uint8_t len,
+  uint16_t len,
   volatile uint8_t *buf,
   volatile uint8_t *out,
   volatile uint8_t *flags
diff --git a/src/apdu-signature.c b/src/apdu-signature.c
index e013f51..9e233fe 100644
--- a/src/apdu-signature.c
+++ b/src/apdu-signature.c
@@ -158,7 +158,7 @@ static ledger_blake2b_ctx blake2;
 static inline bool
 parse_item(
   volatile uint8_t **buf,
-  uint8_t *len,
+  uint16_t *len,
   uint8_t *item,
   size_t item_sz,
   ledger_blake2b_ctx *hash
@@ -193,7 +193,7 @@ parse_item(
 static inline bool
 parse_addr(
   volatile uint8_t **buf,
-  uint8_t *len,
+  uint16_t *len,
   uint8_t *addr_hash,
   uint8_t *addr_len,
   ledger_blake2b_ctx *hash
@@ -228,7 +228,7 @@ parse_addr(
 static inline bool
 parse_name(
   volatile uint8_t **buf,
-  uint8_t *len,
+  uint16_t *len,
   char *name,
   uint8_t *name_len,
   ledger_blake2b_ctx *hash
@@ -269,7 +269,7 @@ parse_name(
 static inline bool
 cmp_name(
   volatile uint8_t **buf,
-  uint8_t *len,
+  uint16_t *len,
   uint8_t *name_hash,
   char *name,
   uint8_t *name_len
@@ -313,7 +313,7 @@ cmp_name(
 static inline bool
 parse_resource_len(
   volatile uint8_t **buf,
-  uint8_t *len,
+  uint16_t *len,
   hns_varint_t *ctr,
   ledger_blake2b_ctx *hash
 ) {
@@ -346,7 +346,7 @@ parse_resource_len(
 static inline bool
 parse_resource(
   volatile uint8_t **buf,
-  uint8_t *len,
+  uint16_t *len,
   hns_varint_t *ctr,
   ledger_blake2b_ctx *hash
 ) {
@@ -365,6 +365,7 @@ parse_resource(
     if (*ctr > 0) {
       if (*len != 0)
         THROW(HNS_INCORRECT_PARSER_STATE);
+
       return false;
     }
   }
@@ -391,7 +392,7 @@ parse_resource(
 static inline uint8_t
 parse(
   uint8_t p1,
-  uint8_t *len,
+  uint16_t *len,
   volatile uint8_t *buf,
   volatile uint8_t *res,
   volatile uint8_t *flags
@@ -987,7 +988,7 @@ parse(
 static inline uint8_t
 sign(
   uint8_t p1,
-  uint8_t *len,
+  uint16_t *len,
   volatile uint8_t *buf,
   volatile uint8_t *sig,
   volatile uint8_t *flags
@@ -1239,11 +1240,11 @@ sign(
   return 65;
 }
 
-uint8_t
+uint16_t
 hns_apdu_get_input_signature(
   uint8_t p1,
   uint8_t p2,
-  uint8_t len,
+  uint16_t len,
   volatile uint8_t *in,
   volatile uint8_t *out,
   volatile uint8_t *flags
diff --git a/src/apdu.h b/src/apdu.h
index bdf60fd..42ddeca 100644
--- a/src/apdu.h
+++ b/src/apdu.h
@@ -295,11 +295,11 @@ hns_apdu_get_app_version(
  * @return the status word
  */
 
-uint8_t
+uint16_t
 hns_apdu_get_public_key(
   uint8_t p1,
   uint8_t p2,
-  uint8_t len,
+  uint16_t len,
   volatile uint8_t *in,
   volatile uint8_t *out,
   volatile uint8_t *flags
@@ -320,11 +320,11 @@ hns_apdu_get_public_key(
  * @return the status word
  */
 
-uint8_t
+uint16_t
 hns_apdu_get_input_signature(
   uint8_t p1,
   uint8_t p2,
-  uint8_t len,
+  uint16_t len,
   volatile uint8_t *in,
   volatile uint8_t *out,
   volatile uint8_t *flags
diff --git a/src/ledger.c b/src/ledger.c
index a09b3bc..3cb6051 100644
--- a/src/ledger.c
+++ b/src/ledger.c
@@ -119,11 +119,11 @@ ledger_apdu_cache_write(volatile uint8_t *src, uint8_t src_len) {
 }
 
 uint8_t
-ledger_apdu_cache_flush(uint8_t *len) {
+ledger_apdu_cache_flush(uint16_t *len) {
   uint8_t *cache = g_ledger_apdu_cache;
   uint8_t *buffer = g_ledger_apdu_buffer;
   uint8_t cache_len = g_ledger_apdu_cache_len;
-  uint8_t buffer_len = 0;
+  uint16_t buffer_len = 0;
 
   if (cache_len == 0)
     return 0;
diff --git a/src/ledger.h b/src/ledger.h
index df36fcc..7818c03 100644
--- a/src/ledger.h
+++ b/src/ledger.h
@@ -168,7 +168,7 @@ ledger_apdu_cache_write(volatile uint8_t *src, uint8_t src_len);
  * @return the amount of data added to the exchange buffer from the cache.
  */
 uint8_t
-ledger_apdu_cache_flush(uint8_t *len);
+ledger_apdu_cache_flush(uint16_t *len);
 
 /**
  * Checks the apdu cache buffer for stored data.
diff --git a/src/utils.h b/src/utils.h
index 1588afc..3b4c48e 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -239,7 +239,7 @@ size_varsize(size_t val) {
 }
 
 static inline bool
-read_u8(volatile uint8_t **buf, uint8_t *len, uint8_t *u8) {
+read_u8(volatile uint8_t **buf, uint16_t *len, uint8_t *u8) {
   if (*len < 1)
     return false;
 
@@ -251,7 +251,7 @@ read_u8(volatile uint8_t **buf, uint8_t *len, uint8_t *u8) {
 }
 
 static inline bool
-read_u16(volatile uint8_t **buf, uint8_t *len, uint16_t *u16, bool be) {
+read_u16(volatile uint8_t **buf, uint16_t *len, uint16_t *u16, bool be) {
   if (*len < 2)
     return false;
 
@@ -270,7 +270,7 @@ read_u16(volatile uint8_t **buf, uint8_t *len, uint16_t *u16, bool be) {
 }
 
 static inline bool
-read_u32(volatile uint8_t **buf, uint8_t *len, uint32_t *u32, bool be) {
+read_u32(volatile uint8_t **buf, uint16_t *len, uint32_t *u32, bool be) {
   if (*len < 4)
     return false;
 
@@ -291,7 +291,7 @@ read_u32(volatile uint8_t **buf, uint8_t *len, uint32_t *u32, bool be) {
 }
 
 static inline bool
-read_varint(volatile uint8_t **buf, uint8_t *len, hns_varint_t *varint) {
+read_varint(volatile uint8_t **buf, uint16_t *len, hns_varint_t *varint) {
   if (*len < 1)
     return false;
 
@@ -350,7 +350,7 @@ read_varint(volatile uint8_t **buf, uint8_t *len, hns_varint_t *varint) {
 }
 
 static inline bool
-peek_varint(volatile uint8_t **buf, uint8_t *len, hns_varint_t *varint) {
+peek_varint(volatile uint8_t **buf, uint16_t *len, hns_varint_t *varint) {
   if (!read_varint(buf, len, varint))
     return false;
 
@@ -363,7 +363,7 @@ peek_varint(volatile uint8_t **buf, uint8_t *len, hns_varint_t *varint) {
 }
 
 static inline bool
-read_varsize(volatile uint8_t **buf, uint8_t *len, size_t *val) {
+read_varsize(volatile uint8_t **buf, uint16_t *len, size_t *val) {
   hns_varint_t v;
 
   if (!read_varint(buf, len, &v))
@@ -375,7 +375,7 @@ read_varsize(volatile uint8_t **buf, uint8_t *len, size_t *val) {
 }
 
 static inline bool
-read_bytes(volatile uint8_t **buf, uint8_t *len, volatile uint8_t *out, size_t sz) {
+read_bytes(volatile uint8_t **buf, uint16_t *len, volatile uint8_t *out, size_t sz) {
   if (*len < sz)
     return false;
 
@@ -390,7 +390,7 @@ read_bytes(volatile uint8_t **buf, uint8_t *len, volatile uint8_t *out, size_t s
 static inline bool
 read_varbytes(
   volatile uint8_t **buf,
-  uint8_t *len,
+  uint16_t *len,
   uint8_t *out,
   size_t out_sz,
   size_t *out_len
@@ -412,6 +412,7 @@ read_varbytes(
   if (!read_bytes(buf, len, out, sz)) {
     *buf -= offset;
     *len += offset;
+
     return false;
   }
 
@@ -423,7 +424,7 @@ read_varbytes(
 static inline bool
 read_bip44_path(
   volatile uint8_t **buf,
-  uint8_t *len,
+  uint16_t *len,
   uint8_t *depth,
   uint32_t *path,
   uint8_t *info