diff --git a/builder/utils/env.py b/builder/utils/env.py
index c9f53a4..f56db6a 100644
--- a/builder/utils/env.py
+++ b/builder/utils/env.py
@@ -8,6 +8,7 @@ from subprocess import PIPE, Popen
 from typing import Dict
 
 from ltchiptool import Family, get_version
+from ltchiptool.util.misc import sizeof
 from platformio.platform.base import PlatformBase
 from platformio.platform.board import PlatformBoardConfig
 from SCons.Script import DefaultEnvironment, Environment
@@ -121,8 +122,10 @@ def env_print_info(
     # Print custom flash layout
     if env.get("FLASH_IS_CUSTOM", False):
         print("CUSTOM FLASH LAYOUT:")
-        for k, v in board.get("flash").items():
-            print(f" - {k}: {v}")
+        for name, layout in board.get("flash").items():
+            (_, _, length) = v.partition("+")
+            length = int(length, 16)
+            print(f" - {name}: {layout} ({sizeof(length)})")
 
 
 def env_parse_custom_options(env: Environment, platform: PlatformBase):
diff --git a/builder/utils/flash.py b/builder/utils/flash.py
index af521e5..59ebd52 100644
--- a/builder/utils/flash.py
+++ b/builder/utils/flash.py
@@ -93,7 +93,7 @@ def env_generate_linker_script(env: Environment, board: PlatformBoardConfig, nam
     with open(input, "r") as f:
         ldscript = f.read()
 
-    def transform(match: re.Match[str]):
+    def transform(match: re.Match):
         key = match[1]
         if key in env:
             return env[key]
diff --git a/cores/common/arduino/libraries/common/Update/UpdateUtil.cpp b/cores/common/arduino/libraries/common/Update/UpdateUtil.cpp
index 59c28b2..3d6ac9f 100644
--- a/cores/common/arduino/libraries/common/Update/UpdateUtil.cpp
+++ b/cores/common/arduino/libraries/common/Update/UpdateUtil.cpp
@@ -43,7 +43,7 @@ void UpdateClass::cleanup(uint8_t ardErr, uf2_err_t uf2Err) {
 		printErrorContext1();
 #endif
 
-	free(ctx); // NULL in constructor
+	uf2_ctx_free(ctx); // NULL in constructor
 	ctx = NULL;
 	uf2_info_free(info); // NULL in constructor
 	info = NULL;
diff --git a/platform.json b/platform.json
index 4f032bb..40ba606 100644
--- a/platform.json
+++ b/platform.json
@@ -101,7 +101,7 @@
     },
     "tool-ltchiptool": {
       "type": "uploader",
-      "version": "https://github.com/libretuya/ltchiptool#v2.0.2",
+      "version": "https://github.com/libretuya/ltchiptool#v4.0.0a0",
       "version_prefix": true,
       "note": "This is used only for C/C++ code from ltchiptool."
     },
diff --git a/platform.py b/platform.py
index e5248ea..6d9f412 100644
--- a/platform.py
+++ b/platform.py
@@ -17,7 +17,7 @@ from platformio.platform.base import PlatformBase
 from platformio.platform.board import PlatformBoardConfig
 from semantic_version import SimpleSpec, Version
 
-LTCHIPTOOL_VERSION = "^3.0.0"
+LTCHIPTOOL_VERSION = "^4.0.0"
 
 
 # Install & import tools
@@ -27,7 +27,7 @@ def check_ltchiptool(install: bool):
         print("Installing/updating ltchiptool")
         system(
             f"{sys.executable} -m pip install -U --force-reinstall "
-            f'"ltchiptool >= {LTCHIPTOOL_VERSION}, < 4.0"'
+            f'"ltchiptool >= {LTCHIPTOOL_VERSION}, < 5.0"'
         )
 
         # unload all modules from the old version