diff --git a/builder/family/beken-72xx.py b/builder/family/beken-72xx.py
index 12cd0bd..b54e22b 100644
--- a/builder/family/beken-72xx.py
+++ b/builder/family/beken-72xx.py
@@ -535,7 +535,7 @@ image_app_rblh = "${BUILD_DIR}/image_${MCULC}_app.${FLASH_RBL_OFFSET}.rblh"
 image_ota_rbl = "${BUILD_DIR}/image_${MCULC}_app.ota.rbl"
 env.Replace(
     # linker command (encryption + packaging)
-    LINK="${LTCHIPTOOL} link2bin ${VARIANT} '' ''",
+    LINK="${LTCHIPTOOL} link2bin ${BOARD_JSON} '' ''",
     # UF2OTA input list
     UF2OTA=[
         # app binary image (enc+crc) for flasher
diff --git a/builder/family/realtek-ambz.py b/builder/family/realtek-ambz.py
index 67a6bb8..2a44ec3 100644
--- a/builder/family/realtek-ambz.py
+++ b/builder/family/realtek-ambz.py
@@ -296,7 +296,7 @@ image_ota1 = "${BUILD_DIR}/image_ota1.${FLASH_OTA1_OFFSET}.bin"
 image_ota2 = "${BUILD_DIR}/image_ota2.${FLASH_OTA2_OFFSET}.bin"
 env.Replace(
     # linker command (dual .bin outputs)
-    LINK="${LTCHIPTOOL} link2bin ${VARIANT} xip1 xip2",
+    LINK="${LTCHIPTOOL} link2bin ${BOARD_JSON} xip1 xip2",
     # UF2OTA input list
     UF2OTA=[
         # same OTA images for flasher and device
diff --git a/builder/frameworks/base.py b/builder/frameworks/base.py
index 9d4011b..5d97c4a 100644
--- a/builder/frameworks/base.py
+++ b/builder/frameworks/base.py
@@ -14,10 +14,16 @@ board: PlatformBoardConfig = env.BoardConfig()
 platform: PlatformBase = env.PioPlatform()
 family: Family = env["FAMILY_OBJ"]
 
+# Parse custom options
+env.ParseCustomOptions(platform)
+# Add flash layout C defines
+env.AddFlashLayout(board)
+# Write custom header options
+env.ApplyCustomOptions(platform)
+# Export board manifest for ltchiptool
+env.ExportBoardData(board)
 # Print information about versions and custom options
 env.PrintInfo(platform)
-# Apply custom header options
-env.ApplyCustomOptions(platform)
 
 # TODO remove include path prepending ("!<...>")
 # Move common core sources (env.AddCoreSources()) and Arduino libs
diff --git a/builder/main.py b/builder/main.py
index b3223c8..36ad3ae 100644
--- a/builder/main.py
+++ b/builder/main.py
@@ -49,10 +49,6 @@ env.Replace(
 
 # Environment variables, include paths, etc.
 env.ConfigureEnvironment(platform, board)
-# Flash layout defines
-env.AddFlashLayout(board)
-# Parse custom options
-env.ParseCustomOptions(platform)
 
 # Family builders details:
 # - call env.AddLibrary("lib name", "base dir", [sources]) to add lib sources
@@ -72,7 +68,7 @@ env.ParseCustomOptions(platform)
 
 # Framework builder (base.py/arduino.py) is executed in BuildProgram()
 # Force including the base framework in case no other is specified
-if not env.get("PIOFRAMEWORK"):
+if "nobuild" not in COMMAND_LINE_TARGETS and not env.get("PIOFRAMEWORK"):
     env.SConscript("frameworks/base.py")
 
 #
diff --git a/builder/utils/env.py b/builder/utils/env.py
index f50281d..700ebc1 100644
--- a/builder/utils/env.py
+++ b/builder/utils/env.py
@@ -96,7 +96,7 @@ def env_print_info(env: Environment, platform: PlatformBase):
         k = k.replace("#", ".")
         if isinstance(v, dict):
             print(f"{indent} - {k}:")
-            for k, v in v.items():
+            for k, v in sorted(v.items()):
                 dump(k, v, indent + TAB)
         elif isinstance(v, list):
             print(f"{indent} - {k}:")
@@ -112,7 +112,7 @@ def env_print_info(env: Environment, platform: PlatformBase):
     # Print custom platformio.ini options
     if platform.custom_opts:
         print("CUSTOM OPTIONS:")
-        for k, v in platform.custom_opts.items():
+        for k, v in sorted(platform.custom_opts.items()):
             dump(k, v)
 
 
diff --git a/builder/utils/flash.py b/builder/utils/flash.py
index a25c63f..82593a9 100644
--- a/builder/utils/flash.py
+++ b/builder/utils/flash.py
@@ -17,10 +17,12 @@ def env_add_flash_layout(env: Environment, board):
         for name, layout in flash_layout.items():
             name = name.upper()
             (offset, _, length) = layout.partition("+")
-            defines[f"FLASH_{name}_OFFSET"] = offset
-            defines[f"FLASH_{name}_LENGTH"] = length
+            offset = int(offset, 16)
+            length = int(length, 16)
+            defines[f"FLASH_{name}_OFFSET"] = f"0x{offset:06X}"
+            defines[f"FLASH_{name}_LENGTH"] = f"0x{length:06X}"
             fal_items += f"FAL_PART_TABLE_ITEM({name.lower()},{name})"
-            flash_size = max(flash_size, int(offset, 16) + int(length, 16))
+            flash_size = max(flash_size, offset + length)
         defines["FLASH_LENGTH"] = f"0x{flash_size:06X}"
         # for "root" partition
         defines["FLASH_ROOT_OFFSET"] = "0x000000"
diff --git a/builder/utils/ltchiptool.py b/builder/utils/ltchiptool.py
index 10b765b..fc1238d 100644
--- a/builder/utils/ltchiptool.py
+++ b/builder/utils/ltchiptool.py
@@ -1,9 +1,11 @@
 # Copyright (c) Kuba Szczodrzyński 2022-06-02.
 
+import json
 from datetime import datetime
 from os.path import basename, join, normpath
 
 from platformio.platform.base import PlatformBase
+from platformio.platform.board import PlatformBoardConfig
 from SCons.Script import Builder, DefaultEnvironment, Environment
 
 env: Environment = DefaultEnvironment()
@@ -43,13 +45,12 @@ def env_uf2ota(env: Environment, *args, **kwargs):
     cmd = [
         "@${LTCHIPTOOL} uf2 write",
         *output_opts,
-        "--family ${FAMILY_SHORT_NAME}",
-        "--board ${VARIANT}",
+        "--board ${BOARD_JSON}",
         f"--lt-version {lt_version}",
         f'--fw "{project_name}:{project_version}"',
         f"--date {int(now.timestamp())}",
         "--legacy",
-        *env["UF2OTA"],
+        *(f'"{arg}"' for arg in env["UF2OTA"]),
     ]
 
     for output in outputs:
@@ -72,6 +73,13 @@ def env_flash_write(env: Environment):
         return []
 
 
+def env_export_board_data(env: Environment, board: PlatformBoardConfig):
+    output = join("${BUILD_DIR}", "board.json")
+    with open(env.subst(output), "w") as f:
+        json.dump(board.manifest, f, indent="\t")
+    env["BOARD_JSON"] = output
+
+
 env.Append(
     BUILDERS=dict(
         BuildUF2OTA=Builder(
@@ -80,3 +88,4 @@ env.Append(
     )
 )
 env.AddMethod(env_flash_write, "GetLtchiptoolWriteFlags")
+env.AddMethod(env_export_board_data, "ExportBoardData")
diff --git a/docs/TODO.md b/docs/TODO.md
index 68aee23..937adbc 100644
--- a/docs/TODO.md
+++ b/docs/TODO.md
@@ -30,6 +30,12 @@ Explicit is better than implicit.
 
 - write OpenOCD flashers, using uf2ota library + FAL for partitions (in ltchiptool repository)
 
+### Development
+
+- write Contributor's Guide
+- export LT cores in an Arduino IDE-compatible format (automatically - GitHub Actions)
+- consider using precompiled SDK blobs for improved build speed (especially on e.g. Raspberry Pi)
+
 ### Serial
 
 - configuration of RX/TX pins
diff --git a/platform.py b/platform.py
index 18256a1..e5248ea 100644
--- a/platform.py
+++ b/platform.py
@@ -2,11 +2,12 @@
 
 import importlib
 import json
+import os
 import platform
 import sys
 from os import system
 from os.path import dirname
-from typing import Dict
+from typing import Dict, List
 
 import click
 from platformio.debug.config.base import DebugConfigBase
@@ -114,7 +115,10 @@ class LibretuyaPlatform(PlatformBase):
     def print(self, *args, **kwargs):
         if not self.verbose:
             return
-        print(*args, **kwargs)
+        print(f"platform.py({os.getpid()}):", *args, **kwargs)
+
+    def custom(self, key: str) -> object:
+        return self.custom_opts.get(key, None)
 
     def get_package_spec(self, name, version=None):
         # make PlatformIO detach existing package versions instead of overwriting
@@ -124,12 +128,13 @@ class LibretuyaPlatform(PlatformBase):
         spec._name_is_custom = False
         return spec
 
-    def configure_default_packages(self, options, targets):
+    def configure_default_packages(self, options: dict, targets: List[str]):
         from ltchiptool.util.dict import RecursiveDict
 
         self.verbose = (
             "-v" in sys.argv or "--verbose" in sys.argv or "PIOVERBOSE=1" in sys.argv
         )
+        self.print(f"configure_default_packages(targets={targets})")
 
         pioframework = options.get("pioframework") or ["base"]
         if not pioframework:
@@ -272,10 +277,8 @@ class LibretuyaPlatform(PlatformBase):
 
         return super().configure_default_packages(options, targets)
 
-    def custom(self, key: str) -> object:
-        return self.custom_opts.get(key, None)
-
     def get_boards(self, id_=None):
+        self.print(f"get_boards(id_={id_})")
         result = PlatformBase.get_boards(self, id_)
         if not result:
             return result
@@ -289,6 +292,14 @@ class LibretuyaPlatform(PlatformBase):
     def update_board(self, board: PlatformBoardConfig):
         if "_base" in board:
             board._manifest = ltchiptool.Board.get_data(board._manifest)
+            board._manifest.pop("_base")
+
+        if self.custom("board"):
+            from ltchiptool.util.dict import merge_dicts
+
+            with open(self.custom("board"), "r") as f:
+                custom_board = json.load(f)
+            board._manifest = merge_dicts(board._manifest, custom_board)
 
         family = board.get("build.family")
         family = ltchiptool.Family.get(short_name=family)
@@ -310,7 +321,8 @@ class LibretuyaPlatform(PlatformBase):
         if "custom" not in debug["tools"]:
             debug["tools"]["custom"] = {}
         init = debug.get("gdb_init", [])
-        init += ["set mem inaccessible-by-default off"]
+        if "set mem inaccessible-by-default off" not in init:
+            init += ["set mem inaccessible-by-default off"]
 
         for link in protocols:
             if link == "openocd":