diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 749366e75..38e8cce22 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -135,7 +135,7 @@ jobs:
         id: depends
         run: |
           sudo apt-get update
-          sudo apt-get install build-essential libvulkan-dev glslc
+          sudo apt-get install build-essential libvulkan-dev glslc spirv-headers
 
       - name: Build
         id: cmake_build
diff --git a/.gitmodules b/.gitmodules
index 5ccdc3824..a26210d90 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,6 +1,6 @@
 [submodule "ggml"]
     path = ggml
-	url = https://github.com/ggml-org/ggml.git
+	url = https://github.com/leejet/ggml.git
 [submodule "examples/server/frontend"]
 	path = examples/server/frontend
 	url = https://github.com/leejet/sdcpp-webui.git
diff --git a/Dockerfile.vulkan b/Dockerfile.vulkan
index 5ba6cb05d..74f2e1e58 100644
--- a/Dockerfile.vulkan
+++ b/Dockerfile.vulkan
@@ -2,7 +2,7 @@ ARG UBUNTU_VERSION=24.04
 
 FROM ubuntu:$UBUNTU_VERSION AS build
 
-RUN apt-get update && apt-get install -y --no-install-recommends build-essential git cmake libvulkan-dev glslc
+RUN apt-get update && apt-get install -y --no-install-recommends build-essential git cmake libvulkan-dev glslc spirv-headers
 
 WORKDIR /sd.cpp
 
diff --git a/docs/build.md b/docs/build.md
index dbc87691e..d33f9329a 100644
--- a/docs/build.md
+++ b/docs/build.md
@@ -102,6 +102,11 @@ cmake --build . --config Release
 ## Build with Vulkan
 
 Install Vulkan SDK from https://www.lunarg.com/vulkan-sdk/.
+On Ubuntu, install the Vulkan development packages and SPIR-V headers:
+
+```shell
+sudo apt-get install build-essential libvulkan-dev glslc spirv-headers
+```
 
 ```shell
 mkdir build && cd build
diff --git a/ggml b/ggml
index 404fcb9d7..c96d3003b 160000
--- a/ggml
+++ b/ggml
@@ -1 +1 @@
-Subproject commit 404fcb9d7c96989569e68c9e7881ee3465a05c50
+Subproject commit c96d3003b2a95b6f7ad33a28f69a4381549043e8
diff --git a/src/ggml_extend.hpp b/src/ggml_extend.hpp
index 859270cbd..ac0ce45db 100644
--- a/src/ggml_extend.hpp
+++ b/src/ggml_extend.hpp
@@ -1356,13 +1356,9 @@ __STATIC_INLINE__ ggml_tensor* ggml_ext_attention_ext(ggml_context* ctx,
 
     float scale = (1.0f / sqrt((float)d_head));
 
-    int kv_pad       = 0;
     ggml_tensor* kqv = nullptr;
 
     auto build_kqv = [&](ggml_tensor* q_in, ggml_tensor* k_in, ggml_tensor* v_in, ggml_tensor* mask_in) -> ggml_tensor* {
-        if (kv_pad != 0) {
-            k_in = ggml_pad(ctx, k_in, 0, kv_pad, 0, 0);
-        }
         if (kv_scale != 1.0f) {
             k_in = ggml_ext_scale(ctx, k_in, kv_scale);
         }
@@ -1370,9 +1366,6 @@ __STATIC_INLINE__ ggml_tensor* ggml_ext_attention_ext(ggml_context* ctx,
 
         v_in = ggml_ext_cont(ctx, ggml_permute(ctx, v_in, 0, 2, 1, 3));
         v_in = ggml_reshape_3d(ctx, v_in, d_head, L_k, n_kv_head * N);
-        if (kv_pad != 0) {
-            v_in = ggml_pad(ctx, v_in, 0, kv_pad, 0, 0);
-        }
         if (kv_scale != 1.0f) {
             v_in = ggml_ext_scale(ctx, v_in, kv_scale);
         }
@@ -1380,26 +1373,9 @@ __STATIC_INLINE__ ggml_tensor* ggml_ext_attention_ext(ggml_context* ctx,
 
         if (mask_in != nullptr) {
             mask_in = ggml_transpose(ctx, mask_in);
-        } else {
-            if (kv_pad > 0) {
-                mask_in         = ggml_ext_zeros(ctx, L_k, L_q, 1, 1);
-                auto pad_tensor = ggml_ext_full(ctx, -INFINITY, kv_pad, L_q, 1, 1);
-                mask_in         = ggml_concat(ctx, mask_in, pad_tensor, 0);
-            }
         }
 
         if (mask_in != nullptr) {
-            // the need for padding got removed in ggml 4767bda
-            // ensure we can still use the old version for now
-#ifdef GGML_KQ_MASK_PAD
-            int mask_pad = 0;
-            if (mask_in->ne[1] % GGML_KQ_MASK_PAD != 0) {
-                mask_pad = GGML_PAD(L_q, GGML_KQ_MASK_PAD) - mask_in->ne[1];
-            }
-            if (mask_pad > 0) {
-                mask_in = ggml_pad(ctx, mask_in, 0, mask_pad, 0, 0);
-            }
-#endif
             mask_in = ggml_cast(ctx, mask_in, GGML_TYPE_F16);
         }
 
@@ -1414,10 +1390,6 @@ __STATIC_INLINE__ ggml_tensor* ggml_ext_attention_ext(ggml_context* ctx,
     if (flash_attn) {
         // LOG_DEBUG("attention_ext L_q:%d L_k:%d n_head:%d C:%d d_head:%d N:%d", L_q, L_k, n_head, C, d_head, N);
         bool can_use_flash_attn = true;
-        if (can_use_flash_attn && L_k % 256 != 0) {
-            kv_pad = GGML_PAD(L_k, 256) - static_cast<int>(L_k);
-        }
-
         if (mask != nullptr) {
             // TODO: figure out if we can bend t5 to work too
             can_use_flash_attn = can_use_flash_attn && mask->ne[3] == 1;