From cc6e4eebada0c77a80bdbdc1830dd9dc1a3ae2f5 Mon Sep 17 00:00:00 2001
From: Awni Hannun <awni@apple.com>
Date: Thu, 29 Jan 2026 13:30:37 -0800
Subject: [PATCH] Fix nax condition for iphone (#3083)

---
 CMakeLists.txt             | 2 +-
 mlx/backend/metal/device.h | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 457d4bf4..041a476c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -329,7 +329,7 @@ else()
   FetchContent_Declare(
     fmt
     GIT_REPOSITORY https://github.com/fmtlib/fmt.git
-    GIT_TAG 10.2.1
+    GIT_TAG 12.1.0
     EXCLUDE_FROM_ALL)
   FetchContent_MakeAvailable(fmt)
 endif()
diff --git a/mlx/backend/metal/device.h b/mlx/backend/metal/device.h
index bf83b8cf..e6162d7d 100644
--- a/mlx/backend/metal/device.h
+++ b/mlx/backend/metal/device.h
@@ -275,8 +275,10 @@ inline bool is_nax_available() {
             macOS 26.2, iOS 26.2, tvOS 26.2, visionOS 26.2, *)) {
       can_use_nax = true;
     }
-    can_use_nax &=
-        metal::device(mlx::core::Device::gpu).get_architecture_gen() >= 17;
+    auto& d = metal::device(mlx::core::Device::gpu);
+    auto arch = d.get_architecture().back();
+    auto gen = d.get_architecture_gen();
+    can_use_nax &= gen >= (arch == 'p' ? 18 : 17);
     return can_use_nax;
   };
   static bool is_nax_available_ = _check_nax();