diff --git a/bazel/config/BUILD.bazel b/bazel/config/BUILD.bazel
index 84eac746e..bf625f6f7 100644
--- a/bazel/config/BUILD.bazel
+++ b/bazel/config/BUILD.bazel
@@ -295,7 +295,7 @@ label_flag(
     build_setting_default = "//bazel:empty_cc_lib",
 )
 
-# PICO_BAZEL_CONFIG: PICO_MBEDTL_CONFIG, [Bazel only] The cc_library that provides mbedtls_config.h, default=//bazel:empty_cc_lib, group=pico_mbedtls
+# PICO_BAZEL_CONFIG: PICO_MBEDTLS_CONFIG, [Bazel only] The cc_library that provides mbedtls_config.h, default=//bazel:empty_cc_lib, group=pico_mbedtls
 label_flag(
     name = "PICO_MBEDTLS_CONFIG",
     build_setting_default = "//bazel:empty_cc_lib",
diff --git a/tools/compare_build_systems.py b/tools/compare_build_systems.py
index 583e51838..c76a92f0c 100755
--- a/tools/compare_build_systems.py
+++ b/tools/compare_build_systems.py
@@ -68,8 +68,18 @@
     "PICO_TOOLCHAIN_PATH",
     # Bazel uses native --platforms mechanics.
     "PICO_PLATFORM",
+    "PICO_DEFAULT_PLATFORM",
+    "PICO_DEFAULT_RP2350_PLATFORM",
     # Named PICO_TOOLCHAIN in Bazel.
     "PICO_COMPILER",
+    # Bazel uses PICO_COMPILATION_NO_OPT_ARGS and PICO_COMPILATION_NO_DEBUG_ARGS
+    # to allow overriding these flags instead.
+    "PICO_DEOPTIMIZED_DEBUG",
+    "PICO_DEBUG_INFO_IN_RELEASE",
+    # Entirely irrelevant to Bazel, use Bazel toolchains:
+    #     https://bazel.build/extending/toolchains
+    "PICO_TOOLCHAIN_DIR",
+    "PICO_GCC_TRIPLE",
     # Entirely irrelevant to Bazel, use Bazel platforms:
     #     https://bazel.build/extending/platforms
     "PICO_CMAKE_PRELOAD_PLATFORM_FILE",
@@ -81,22 +91,44 @@
     "PICO_CONFIG_HEADER_FILES",
     "PICO_RP2040_CONFIG_HEADER_FILES",
     "PICO_HOST_CONFIG_HEADER_FILES",
+    "PICO_RP2350_ARM_S_CONFIG_HEADER_FILES",
+    "PICO_RP2350_RISCV_CONFIG_HEADER_FILES",
     # Bazel uses PICO_CONFIG_HEADER.
     "PICO_BOARD_CMAKE_DIRS",
     "PICO_BOARD_HEADER_FILE",
     "PICO_BOARD_HEADER_DIRS",
+    # Bazel handles default boards differently.
+    "PICO_DEFAULT_BOARD_rp2040",
+    "PICO_DEFAULT_BOARD_rp2350",
+    "PICO_DEFAULT_BOARD_host",
+    # Bazel doesn't provide a way of overriding the defaults for this.
+    # TODO: Provide a way to customise these toolchain flags.
+    "PICO_HARD_FLOAT_ABI",
+    "PICO_NO_CMSE",
     # Bazel supports this differently.
     # TODO: Provide a helper rule for explicitly generating a UF2 so users don't
     # have to write out a bespoke run_binary.
     "PICO_NO_UF2",
+    "PICO_NO_COPRO_DIS",
+    "PICO_ALLOW_EXAMPLE_KEYS",
     # Bazel will not provide a default for this.
     # TODO: Provide handy rules for PIOASM so users don't have to write out a
     # bespoke run_binary.
     "PICO_DEFAULT_PIOASM_OUTPUT_FORMAT",
     # Bazel always has picotool.
     "PICO_NO_PICOTOOL",
-    # These aren't supported as build flags in Bazel. Prefer to
-    # set these in board header files like other SDK defines.
+    # Bazel includes these differently.
+    "PICO_TINYUSB_PATH",
+    "PICO_BTSTACK_PATH",
+    "PICO_CYW43_DRIVER_PATH",
+    "PICO_MBEDTLS_PATH",
+    "PICO_LWIP_PATH",
+    # These are legacy CMake options that should not be used.
+    "PICO_NO_FLASH",
+    "PICO_COPY_TO_RAM",
+    # These aren't supported as build flags in CMake either, but they appear
+    # as comments which this script can't tell.
+    "CYW43_PIN_WL_DYNAMIC",
     "CYW43_DEFAULT_PIN_WL_REG_ON",
     "CYW43_DEFAULT_PIN_WL_DATA_OUT",
     "CYW43_DEFAULT_PIN_WL_DATA_IN",
@@ -105,6 +137,7 @@
     "CYW43_DEFAULT_PIN_WL_CS",
     "CYW43_PIO_CLOCK_DIV_INT",
     "CYW43_PIO_CLOCK_DIV_FRAC",
+    "CYW43_PIO_CLOCK_DIV_FRAC8",
     "CYW43_PIO_CLOCK_DIV_DYNAMIC",
 )
 
@@ -133,6 +166,7 @@
     # - PICO_BOARD_HEADER_DIRS
     "PICO_CONFIG_HEADER",
     # Bazel configuration for 3p deps.
+    "PICO_TINYUSB_CONFIG",
     "PICO_BTSTACK_CONFIG",
     "PICO_LWIP_CONFIG",
     "PICO_MBEDTLS_CONFIG",