diff --git a/src/apps/wallet/sign_tx/scripts.py b/src/apps/wallet/sign_tx/scripts.py
index 6e8a97da17..d2bf850272 100644
--- a/src/apps/wallet/sign_tx/scripts.py
+++ b/src/apps/wallet/sign_tx/scripts.py
@@ -42,21 +42,18 @@ def output_script_p2sh(scripthash: bytes) -> bytearray:
     return s
 
 
-def script_replay_protection_bip115(block_hash: bytes, block_height: bytes) -> bytearray:
+def script_replay_protection_bip115(block_hash: bytes, block_height: int) -> bytearray:
     if block_hash is None or block_height is None:
         return bytearray()
-    block_height_size = len(block_height)  # size in bytes of block_height (should be 3)
-    s = bytearray(38)
+    assert len(block_hash) == 32
+    s = bytearray(33)
     s[0] = 0x20  # 32 bytes for block hash
     s[1:33] = block_hash  # block hash
-    s[33] = 0x03  # 3 bytes for block height
-    if block_height_size == 3:
-        s[34:37] = block_height
-    else:
-        s[34:37] = block_height[:3 - block_height_size]  # must be only 3 bytes
-    s[37] = 0xB4  # OP_CHECKBLOCKHIGHT
+    write_scriptnum(s, block_height)
+    s.append(0xB4)  # OP_CHECKBLOCKATHEIGHT
     return s
 
+
 # SegWit: Native P2WPKH or P2WSH
 # ===
 # https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki#p2wpkh
diff --git a/src/apps/wallet/sign_tx/writers.py b/src/apps/wallet/sign_tx/writers.py
index fae6724cfd..634cbb1873 100644
--- a/src/apps/wallet/sign_tx/writers.py
+++ b/src/apps/wallet/sign_tx/writers.py
@@ -59,7 +59,7 @@ def write_varint(w, n: int):
     assert n >= 0 and n <= 0xFFFFFFFF
     if n < 253:
         w.append(n & 0xFF)
-    elif n < 65536:
+    elif n < 0x10000:
         w.append(253)
         w.append(n & 0xFF)
         w.append((n >> 8) & 0xFF)
@@ -71,6 +71,28 @@ def write_varint(w, n: int):
         w.append((n >> 24) & 0xFF)
 
 
+def write_scriptnum(w, n: int):
+    assert n >= 0 and n <= 0xFFFFFFFF
+    if n < 0x100:
+        w.append(1)
+        w.append(n & 0xFF)
+    elif n < 0x10000:
+        w.append(2)
+        w.append(n & 0xFF)
+        w.append((n >> 8) & 0xFF)
+    elif n < 0x1000000:
+        w.append(3)
+        w.append(n & 0xFF)
+        w.append((n >> 8) & 0xFF)
+        w.append((n >> 16) & 0xFF)
+    elif:
+        w.append(4)
+        w.append(n & 0xFF)
+        w.append((n >> 8) & 0xFF)
+        w.append((n >> 16) & 0xFF)
+        w.append((n >> 24) & 0xFF)
+
+
 def write_uint32(w, n: int):
     assert n >= 0 and n <= 0xFFFFFFFF
     w.append(n & 0xFF)
diff --git a/src/trezor/messages/TxInputType.py b/src/trezor/messages/TxInputType.py
index 88243a49fd..130d1be328 100644
--- a/src/trezor/messages/TxInputType.py
+++ b/src/trezor/messages/TxInputType.py
@@ -22,7 +22,7 @@ class TxInputType(p.MessageType):
         9: ('decred_tree', p.UVarintType, 0),
         10: ('decred_script_version', p.UVarintType, 0),
         11: ('prev_block_hash_bip115', p.BytesType, 0),
-        12: ('prev_block_height_bip115', p.BytesType, 0),
+        12: ('prev_block_height_bip115', p.UVarintType, 0),
     }
 
     def __init__(
@@ -38,7 +38,7 @@ class TxInputType(p.MessageType):
         decred_tree: int = None,
         decred_script_version: int = None,
         prev_block_hash_bip115: bytes = None,
-        prev_block_height_bip115: bytes = None,
+        prev_block_height_bip115: int = None,
     ) -> None:
         self.address_n = address_n if address_n is not None else []
         self.prev_hash = prev_hash
diff --git a/src/trezor/messages/TxOutputType.py b/src/trezor/messages/TxOutputType.py
index 1c5d7abe45..cc3bd9d37b 100644
--- a/src/trezor/messages/TxOutputType.py
+++ b/src/trezor/messages/TxOutputType.py
@@ -19,7 +19,7 @@ class TxOutputType(p.MessageType):
         6: ('op_return_data', p.BytesType, 0),
         7: ('decred_script_version', p.UVarintType, 0),
         8: ('block_hash_bip115', p.BytesType, 0),
-        9: ('block_height_bip115', p.BytesType, 0),
+        9: ('block_height_bip115', p.UVarintType, 0),
     }
 
     def __init__(
@@ -32,7 +32,7 @@ class TxOutputType(p.MessageType):
         op_return_data: bytes = None,
         decred_script_version: int = None,
         block_hash_bip115: bytes = None,
-        block_height_bip115: bytes = None,
+        block_height_bip115: int = None,
     ) -> None:
         self.address = address
         self.address_n = address_n if address_n is not None else []
diff --git a/vendor/trezor-common b/vendor/trezor-common
index 1b9b7d6c8e..5eae03131c 160000
--- a/vendor/trezor-common
+++ b/vendor/trezor-common
@@ -1 +1 @@
-Subproject commit 1b9b7d6c8ed44b24a7f105a83dc10ea7cc796ed9
+Subproject commit 5eae03131c89dabaa4caa8c5cb96742707206541