diff --git a/cpython-unix/build-cpython.sh b/cpython-unix/build-cpython.sh
index 132d24a40..f05c60223 100755
--- a/cpython-unix/build-cpython.sh
+++ b/cpython-unix/build-cpython.sh
@@ -649,6 +649,14 @@ if [[ -n "${PYTHON_MEETS_MINIMUM_VERSION_3_13}" && "${TARGET_TRIPLE}" == x86_64*
     PROFILE_TASK="${PROFILE_TASK} --ignore test.test_bytes.BytesTest.test_from_format"
 fi
 
+# LLVM 23's BOLT instrumentation exhausts the stack in these recursion tests.
+if [[ -n "${PYTHON_MEETS_MINIMUM_VERSION_3_14}" && -n "${BOLT_CAPABLE}" && "${LLVM_VERSION}" = 23 && "${TARGET_TRIPLE}" == x86_64* ]]; then
+    PROFILE_TASK="${PROFILE_TASK} --ignore test.test_json.test_recursion.TestCRecursion.test_endless_recursion"
+    PROFILE_TASK="${PROFILE_TASK} --ignore test.test_functools.TestLRUC.test_lru_recursion"
+    PROFILE_TASK="${PROFILE_TASK} --ignore test.test_functools.*.test_recursive_pickle"
+    PROFILE_TASK="${PROFILE_TASK} --ignore test.test_xml_etree_c.BadElementTest.test_deeply_nested_deepcopy"
+fi
+
 # We use ndbm on macOS and BerkeleyDB elsewhere.
 if [[ "${PYBUILD_PLATFORM}" = macos* ]]; then
     CONFIGURE_FLAGS="${CONFIGURE_FLAGS} --with-dbmliborder=ndbm"
diff --git a/cpython-unix/build-tk.sh b/cpython-unix/build-tk.sh
index c60aab599..5dae32922 100755
--- a/cpython-unix/build-tk.sh
+++ b/cpython-unix/build-tk.sh
@@ -26,6 +26,13 @@ LDFLAGS="${EXTRA_TARGET_LDFLAGS}"
 if [[ "${PYBUILD_PLATFORM}" = macos* ]]; then
     CFLAGS="${CFLAGS} -I${TOOLS_PATH}/deps/include -Wno-availability"
     CFLAGS="${CFLAGS} -Wno-deprecated-declarations -Wno-unknown-attributes -Wno-typedef-redefinition"
+    # Clang 23 emits Objective-C class selector stubs that ld64.lld cannot link.
+    # Probe the flag because older macOS toolchains do not recognize it.
+    # lld from LLVM 23 does not yet support theses stubs
+    # https://github.com/llvm/llvm-project/pull/219744
+    if "${CC}" -fno-objc-msgsend-class-selector-stubs -x objective-c -fsyntax-only /dev/null >/dev/null 2>&1; then
+        CFLAGS="${CFLAGS} -fno-objc-msgsend-class-selector-stubs"
+    fi
     LDFLAGS="${LDFLAGS} -L${TOOLS_PATH}/deps/lib"
     EXTRA_CONFIGURE_FLAGS="--enable-aqua=yes --without-x"
 else
diff --git a/cpython-unix/patch-jit-llvm-version-3.13.patch b/cpython-unix/patch-jit-llvm-version-3.13.patch
index f980855d7..5b484d949 100644
--- a/cpython-unix/patch-jit-llvm-version-3.13.patch
+++ b/cpython-unix/patch-jit-llvm-version-3.13.patch
@@ -7,7 +7,7 @@ index b68da1b6be1..cf04f83539e 100644
  import typing
  
 -_LLVM_VERSION = 18
-+_LLVM_VERSION = 22
++_LLVM_VERSION = int(os.environ.get("LLVM_VERSION", "18"))
  _LLVM_VERSION_PATTERN = re.compile(
      rf"(?<!Apple )(LLVM|clang) version\s+{_LLVM_VERSION}\.\d+\.\d+\S*\s+"
  )
diff --git a/cpython-unix/patch-jit-llvm-version-3.14.patch b/cpython-unix/patch-jit-llvm-version-3.14.patch
index a68bfadd2..159a59926 100644
--- a/cpython-unix/patch-jit-llvm-version-3.14.patch
+++ b/cpython-unix/patch-jit-llvm-version-3.14.patch
@@ -6,7 +6,7 @@ diff --git a/Tools/jit/_llvm.py b/Tools/jit/_llvm.py
  import _targets
  
 -_LLVM_VERSION = 19
-+_LLVM_VERSION = 22
++_LLVM_VERSION = int(os.environ.get("LLVM_VERSION", "19"))
  _LLVM_VERSION_PATTERN = re.compile(
      rf"(?<!Apple )(LLVM|clang) version\s+{_LLVM_VERSION}\.\d+\.\d+\S*\s+"
  )
diff --git a/cpython-unix/targets.yml b/cpython-unix/targets.yml
index 9ebe96884..2088b3908 100644
--- a/cpython-unix/targets.yml
+++ b/cpython-unix/targets.yml
@@ -72,7 +72,6 @@
 aarch64-apple-darwin:
   host_platforms:
     - macos_arm64
-    - macos_x86_64
   pythons_supported:
     - '3.10'
     - '3.11'
@@ -636,7 +635,6 @@ s390x-unknown-linux-gnu:
 x86_64-apple-darwin:
   host_platforms:
     - macos_arm64
-    - macos_x86_64
   pythons_supported:
     - '3.10'
     - '3.11'
diff --git a/pythonbuild/downloads.json b/pythonbuild/downloads.json
index 4d19a1579..9b0a1c127 100644
--- a/pythonbuild/downloads.json
+++ b/pythonbuild/downloads.json
@@ -213,28 +213,22 @@
         "version": "7.0.12-2~bpo13+1"
     },
     "llvm-aarch64-linux": {
-        "url": "https://github.com/indygreg/toolchain-tools/releases/download/toolchain-bootstrap%2F20260410/llvm-22.1.3+20260410-gnu_only-aarch64-unknown-linux-gnu.tar.zst",
-        "size": 237655768,
-        "sha256": "9cb4b562323a3d899fffe6393148e92447e17b69a2501d7c6e7f2a86c32cddc1",
-        "version": "22.1.3+20260410"
+        "url": "https://github.com/astral-sh/llvm-build/releases/download/20260925/llvm-23.1.2+20260925-gnu_only-aarch64-unknown-linux-gnu.tar.zst",
+        "size": 219511882,
+        "sha256": "fe4dc64a553ada62fdbd732234cc6db4bab60c8516f9ea520c4abea7b646c900",
+        "version": "23.1.2+20260925"
     },
     "llvm-x86_64-linux": {
-        "url": "https://github.com/indygreg/toolchain-tools/releases/download/toolchain-bootstrap%2F20260410/llvm-22.1.3+20260410-gnu_only-x86_64-unknown-linux-gnu.tar.zst",
-        "size": 281109065,
-        "sha256": "0ee8e4f89c20983d62547b1e665147ee08a7413f478e9e443fa991548da1030d",
-        "version": "22.1.3+20260410"
+        "url": "https://github.com/astral-sh/llvm-build/releases/download/20260925/llvm-23.1.2+20260925-gnu_only-x86_64-unknown-linux-gnu.tar.zst",
+        "size": 227890333,
+        "sha256": "96ea5dcf7663787984f44b3cff25259b0a8cf7cce615331102144cbdde833f9f",
+        "version": "23.1.2+20260925"
     },
     "llvm-aarch64-macos": {
-        "url": "https://github.com/indygreg/toolchain-tools/releases/download/toolchain-bootstrap%2F20260410/llvm-22.1.3+20260410-aarch64-apple-darwin.tar.zst",
-        "size": 159775425,
-        "sha256": "98171836c31c04edec074e5f3fee67fcace4bf3859b68a770dd9ff2039ea127d",
-        "version": "22.1.3+20260410"
-    },
-    "llvm-x86_64-macos": {
-        "url": "https://github.com/indygreg/toolchain-tools/releases/download/toolchain-bootstrap%2F20260410/llvm-22.1.3+20260410-x86_64-apple-darwin.tar.zst",
-        "size": 167376011,
-        "sha256": "15bfda1bc8bc920658c09ef1ebb4593f0705b3314beab23989f14775f2e3f3f0",
-        "version": "22.1.3+20260410"
+        "url": "https://github.com/astral-sh/llvm-build/releases/download/20260925/llvm-23.1.2+20260925-aarch64-apple-darwin.tar.zst",
+        "size": 165484624,
+        "sha256": "2adaeff353a29e60f92a16c9eae603dbbdc9613c04ad6c0fac9a5c4a40dd7eb0",
+        "version": "23.1.2+20260925"
     },
     "m4": {
         "upstream_url": "https://ftp.gnu.org/gnu/m4/m4-1.4.19.tar.xz",
diff --git a/pythonbuild/utils.py b/pythonbuild/utils.py
index a599925aa..ddda5205d 100644
--- a/pythonbuild/utils.py
+++ b/pythonbuild/utils.py
@@ -47,7 +47,9 @@ def current_host_platform() -> str:
         if machine == "arm64":
             return "macos_arm64"
         elif machine == "x86_64":
-            return "macos_x86_64"
+            raise Exception(
+                "macOS builds require an Apple Silicon host running native arm64 Python"
+            )
         else:
             raise Exception(f"unhanded macOS machine type: {machine}")
     elif sys.platform == "win32":
@@ -75,8 +77,6 @@ def default_target_triple() -> str:
         return "aarch64-unknown-linux-gnu"
     elif host == "macos_arm64":
         return "aarch64-apple-darwin"
-    elif host == "macos_x86_64":
-        return "x86_64-apple-darwin"
     elif host == "windows_x86":
         return "i686-pc-windows-msvc"
     elif host == "windows_x86_64":
@@ -506,8 +506,6 @@ def clang_toolchain(host_platform: str, target_triple: str) -> str:
         return "llvm-aarch64-linux"
     elif host_platform == "macos_arm64":
         return "llvm-aarch64-macos"
-    elif host_platform == "macos_x86_64":
-        return "llvm-x86_64-macos"
     else:
         raise Exception("unhandled host platform")
 
diff --git a/scripts/update_downloads.py b/scripts/update_downloads.py
index 1708e521a..814ee4972 100644
--- a/scripts/update_downloads.py
+++ b/scripts/update_downloads.py
@@ -417,7 +417,6 @@ def xorg_policy(category: str, name: str, extension: str = "tar.gz") -> Policy:
     "llvm-aarch64-linux": "toolchain bootstrap requires coordinated updates",
     "llvm-x86_64-linux": "toolchain bootstrap requires coordinated updates",
     "llvm-aarch64-macos": "toolchain bootstrap requires coordinated updates",
-    "llvm-x86_64-macos": "toolchain bootstrap requires coordinated updates",
     "musl": "intentionally pinned build toolchain",
     "musl-static": "intentionally pinned build toolchain",
     "openssl-1.1": "end-of-life release series",