diff --git a/barretenberg/cpp/CMakePresets.json b/barretenberg/cpp/CMakePresets.json
index 420fb003d42e..62b4f4851719 100644
--- a/barretenberg/cpp/CMakePresets.json
+++ b/barretenberg/cpp/CMakePresets.json
@@ -19,7 +19,6 @@
       },
       "cacheVariables": {
         "CMAKE_BUILD_TYPE": "Release",
-        "TARGET_ARCH": "skylake",
         "ENABLE_PIC": "ON"
       }
     },
diff --git a/barretenberg/cpp/bootstrap.sh b/barretenberg/cpp/bootstrap.sh
index a4c70bba834c..7a38e0bd4f80 100755
--- a/barretenberg/cpp/bootstrap.sh
+++ b/barretenberg/cpp/bootstrap.sh
@@ -7,7 +7,6 @@ else
   export native_preset=${NATIVE_PRESET:-clang20-no-avm}
 fi
 export hash=$(hash_str $(../../avm-transpiler/bootstrap.sh hash) $(cache_content_hash .rebuild_patterns))
-export native_build_dir=$(scripts/preset-build-dir)
 
 # Injects version number into a given bb binary.
 # Means we don't actually need to rebuild bb to release a new version if code hasn't changed.
diff --git a/barretenberg/cpp/cmake/arch.cmake b/barretenberg/cpp/cmake/arch.cmake
index 71b6dbb599ff..fe6488cbce3f 100644
--- a/barretenberg/cpp/cmake/arch.cmake
+++ b/barretenberg/cpp/cmake/arch.cmake
@@ -5,7 +5,19 @@ if(WASM)
     add_compile_options(-fno-exceptions -fno-slp-vectorize)
 endif()
 
-if(NOT WASM AND NOT ARM AND TARGET_ARCH)
+# Auto-detect TARGET_ARCH if not explicitly set.
+# Use 'skylake' on x86_64 (matches our cross-compile presets) and 'generic' on ARM
+# to avoid emitting CPU-specific instructions (e.g. SVE on Graviton) that break on
+# other ARM machines like Apple Silicon.
+if(NOT WASM AND NOT TARGET_ARCH)
+    if(ARM)
+        set(TARGET_ARCH "generic")
+    else()
+        set(TARGET_ARCH "skylake")
+    endif()
+endif()
+
+if(NOT WASM AND TARGET_ARCH)
     message(STATUS "Target architecture: ${TARGET_ARCH}")
     add_compile_options(-march=${TARGET_ARCH})
 endif()
diff --git a/barretenberg/cpp/scripts/zig-c++.sh b/barretenberg/cpp/scripts/zig-c++.sh
index 3c1a69cb9ad6..dc7e822e03a4 100755
--- a/barretenberg/cpp/scripts/zig-c++.sh
+++ b/barretenberg/cpp/scripts/zig-c++.sh
@@ -1,6 +1,8 @@
 #!/bin/bash
 # Wrapper for zig c++ that pins glibc 2.35 on Linux (Ubuntu 22.04+ compat)
 # and uses native target on macOS.
+# Note: arch.cmake handles -march selection (skylake on x86, generic on ARM)
+# which overrides zig's native CPU detection, preventing CPU-specific instructions.
 if [[ "$(uname -s)" == "Linux" ]]; then
   exec zig c++ -target native-linux-gnu.2.35 "$@"
 else
diff --git a/barretenberg/cpp/scripts/zig-cc.sh b/barretenberg/cpp/scripts/zig-cc.sh
index 6f1444434676..bc39365b6c09 100755
--- a/barretenberg/cpp/scripts/zig-cc.sh
+++ b/barretenberg/cpp/scripts/zig-cc.sh
@@ -1,6 +1,8 @@
 #!/bin/bash
 # Wrapper for zig cc that pins glibc 2.35 on Linux (Ubuntu 22.04+ compat)
 # and uses native target on macOS.
+# Note: arch.cmake handles -march selection (skylake on x86, generic on ARM)
+# which overrides zig's native CPU detection, preventing CPU-specific instructions.
 if [[ "$(uname -s)" == "Linux" ]]; then
   exec zig cc -target native-linux-gnu.2.35 "$@"
 else
diff --git a/barretenberg/sol/scripts/init_honk.sh b/barretenberg/sol/scripts/init_honk.sh
index cf24ef092aba..5711269ce03c 100755
--- a/barretenberg/sol/scripts/init_honk.sh
+++ b/barretenberg/sol/scripts/init_honk.sh
@@ -1,14 +1,22 @@
 #!/usr/bin/env bash
+set -eu
 # the verification key is the same for ultra and ultra zk
 SRS_PATH="$HOME/.bb-crs"
 OUTPUT_PATH="./src/honk"
+KEYGEN="../cpp/build/bin/honk_solidity_key_gen"
+
+if [ ! -x "$KEYGEN" ]; then
+  echo "Error: honk_solidity_key_gen binary not found at $KEYGEN" >&2
+  echo "Run barretenberg/cpp bootstrap first." >&2
+  exit 1
+fi
 
 mkdir -p './src/honk/keys'
 
-../cpp/build/bin/honk_solidity_key_gen add2 $OUTPUT_PATH $SRS_PATH
-../cpp/build/bin/honk_solidity_key_gen blake $OUTPUT_PATH $SRS_PATH
-../cpp/build/bin/honk_solidity_key_gen ecdsa $OUTPUT_PATH $SRS_PATH
-../cpp/build/bin/honk_solidity_key_gen recursive $OUTPUT_PATH $SRS_PATH
+$KEYGEN add2 $OUTPUT_PATH $SRS_PATH
+$KEYGEN blake $OUTPUT_PATH $SRS_PATH
+$KEYGEN ecdsa $OUTPUT_PATH $SRS_PATH
+$KEYGEN recursive $OUTPUT_PATH $SRS_PATH
 
 echo ""
 echo "✓ VK generation complete"
diff --git a/noir/bootstrap.sh b/noir/bootstrap.sh
index 4fd19781f16a..1fcb30d95250 100755
--- a/noir/bootstrap.sh
+++ b/noir/bootstrap.sh
@@ -25,7 +25,12 @@ function build_native {
   set -euo pipefail
 
   if ! cache_download noir-$hash.tar.gz; then
-    (cd noir-repo && cargo build --locked --release --target-dir target)
+    # Serialize cargo operations to avoid race conditions with avm-transpiler
+    # which may run in parallel and share the same CARGO_HOME.
+    (
+      flock -x 200
+      cd noir-repo && cargo build --locked --release --target-dir target
+    ) 200>/tmp/rustup.lock
     cache_upload noir-$hash.tar.gz noir-repo/target/release/{nargo,acvm,noir-profiler}
   fi
 }