diff --git a/.changeset/baseline-cpu-fallback.md b/.changeset/baseline-cpu-fallback.md
new file mode 100644
index 0000000..a461691
--- /dev/null
+++ b/.changeset/baseline-cpu-fallback.md
@@ -0,0 +1,5 @@
+---
+"@bunny.net/cli": patch
+---
+
+fix(install): ship a baseline (non-AVX2) build for older x64 CPUs that crashed with "Illegal instruction" — the installer auto-selects it, and the npm wrapper falls back to it on SIGILL
diff --git a/.changeset/bsql-baseline-fallback.md b/.changeset/bsql-baseline-fallback.md
new file mode 100644
index 0000000..d4e0a94
--- /dev/null
+++ b/.changeset/bsql-baseline-fallback.md
@@ -0,0 +1,5 @@
+---
+"@bunny.net/database-shell": patch
+---
+
+fix(bsql): fall back to a baseline (non-AVX2) binary on older x64 CPUs that crashed with "Illegal instruction"
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 6bb519d..ba04cde 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -128,6 +128,43 @@ jobs:
           path: packages/${{ matrix.npm-pkg }}/
           if-no-files-found: error
 
+  build-cli-baseline:
+    name: Build ${{ matrix.binary }}
+    needs: version
+    if: needs.version.outputs.cli-version
+    strategy:
+      matrix:
+        include:
+          - target: bun-linux-x64-baseline
+            os: ubuntu-latest
+            binary: bunny-linux-x64-baseline
+          - target: bun-darwin-x64-baseline
+            os: macos-latest
+            binary: bunny-darwin-x64-baseline
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@v5
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: "1.3.11"
+      - run: bun install
+
+      - name: Build database studio
+        run: bun run --filter @bunny.net/database-studio build:client
+
+      # Baseline targets avoid AVX2, so the binary runs on pre-Haswell x64 CPUs that crash the default build with SIGILL.
+      - name: Build binary
+        run: bun build packages/cli/src/index.ts --compile --minify --sourcemap --target=${{ matrix.target }} --outfile ${{ matrix.binary }}
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: ${{ matrix.binary }}
+          path: ${{ matrix.binary }}
+          if-no-files-found: error
+
   build-database-shell-binaries:
     name: Build ${{ matrix.npm-pkg }}
     needs: version
@@ -178,12 +215,47 @@ jobs:
           path: packages/${{ matrix.npm-pkg }}/
           if-no-files-found: error
 
+  build-database-shell-baseline:
+    name: Build ${{ matrix.binary }}
+    needs: version
+    if: needs.version.outputs.database-shell-version
+    strategy:
+      matrix:
+        include:
+          - target: bun-linux-x64-baseline
+            os: ubuntu-latest
+            binary: bsql-linux-x64-baseline
+          - target: bun-darwin-x64-baseline
+            os: macos-latest
+            binary: bsql-darwin-x64-baseline
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@v5
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: "1.3.11"
+      - run: bun install
+
+      # Baseline targets avoid AVX2, so the binary runs on pre-Haswell x64 CPUs that crash the default build with SIGILL.
+      - name: Build binary
+        run: bun build packages/database-shell/src/cli.ts --compile --minify --sourcemap --target=${{ matrix.target }} --outfile ${{ matrix.binary }}
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: ${{ matrix.binary }}
+          path: ${{ matrix.binary }}
+          if-no-files-found: error
+
   publish-cli:
     name: Publish CLI
     runs-on: ubuntu-latest
     needs:
       - version
       - build-cli-binaries
+      - build-cli-baseline
     steps:
       - uses: actions/checkout@v5
 
@@ -203,12 +275,20 @@ jobs:
             cp -r npm-artifacts/$pkg/* packages/$pkg/
           done
 
+      # x64 packages also ship a baseline binary the wrapper falls back to on AVX2-less CPUs.
+      - name: Copy baseline binaries into x64 npm packages
+        run: |
+          cp npm-artifacts/bunny-linux-x64-baseline/bunny-linux-x64-baseline packages/cli-linux-x64/bunny-baseline
+          cp npm-artifacts/bunny-darwin-x64-baseline/bunny-darwin-x64-baseline packages/cli-darwin-x64/bunny-baseline
+
       - name: Set execute permissions
         run: |
           chmod +x packages/cli-linux-x64/bunny
           chmod +x packages/cli-linux-arm64/bunny
           chmod +x packages/cli-darwin-x64/bunny
           chmod +x packages/cli-darwin-arm64/bunny
+          chmod +x packages/cli-linux-x64/bunny-baseline
+          chmod +x packages/cli-darwin-x64/bunny-baseline
 
       - name: Publish platform packages
         run: |
@@ -247,6 +327,8 @@ jobs:
             npm-artifacts/cli-darwin-x64/bunny-darwin-x64
             npm-artifacts/cli-darwin-arm64/bunny-darwin-arm64
             npm-artifacts/cli-windows-x64/bunny-windows-x64.exe
+            npm-artifacts/bunny-linux-x64-baseline/bunny-linux-x64-baseline
+            npm-artifacts/bunny-darwin-x64-baseline/bunny-darwin-x64-baseline
           fail_on_unmatched_files: true
 
   publish-database-shell:
@@ -255,6 +337,7 @@ jobs:
     needs:
       - version
       - build-database-shell-binaries
+      - build-database-shell-baseline
     steps:
       - uses: actions/checkout@v5
 
@@ -274,12 +357,20 @@ jobs:
             cp -r npm-artifacts/$pkg/* packages/$pkg/
           done
 
+      # x64 packages also ship a baseline binary the wrapper falls back to on AVX2-less CPUs.
+      - name: Copy baseline binaries into x64 npm packages
+        run: |
+          cp npm-artifacts/bsql-linux-x64-baseline/bsql-linux-x64-baseline packages/database-shell-linux-x64/bsql-baseline
+          cp npm-artifacts/bsql-darwin-x64-baseline/bsql-darwin-x64-baseline packages/database-shell-darwin-x64/bsql-baseline
+
       - name: Set execute permissions
         run: |
           chmod +x packages/database-shell-linux-x64/bsql
           chmod +x packages/database-shell-linux-arm64/bsql
           chmod +x packages/database-shell-darwin-x64/bsql
           chmod +x packages/database-shell-darwin-arm64/bsql
+          chmod +x packages/database-shell-linux-x64/bsql-baseline
+          chmod +x packages/database-shell-darwin-x64/bsql-baseline
 
       - name: Publish platform packages
         run: |
diff --git a/install.sh b/install.sh
index 3f41ebe..033d64d 100755
--- a/install.sh
+++ b/install.sh
@@ -21,6 +21,14 @@ get_arch() {
   esac
 }
 
+has_avx2() {
+  case "$OS" in
+    linux)  grep -qw avx2 /proc/cpuinfo 2>/dev/null ;;
+    darwin) sysctl -n machdep.cpu.leaf7_features 2>/dev/null | grep -qiw avx2 ;;
+    *)      return 1 ;;
+  esac
+}
+
 OS=$(get_os)
 ARCH=$(get_arch)
 
@@ -30,7 +38,14 @@ if [ "$OS" = "unsupported" ] || [ "$ARCH" = "unsupported" ]; then
   exit 1
 fi
 
-BINARY="bunny-${OS}-${ARCH}"
+# The default Bun-compiled binary uses AVX2; pre-Haswell (~2013) x64 CPUs lack it and crash with "Illegal instruction", so fall back to the baseline build.
+VARIANT=""
+if [ "$ARCH" = "x64" ] && ! has_avx2; then
+  VARIANT="-baseline"
+  echo "AVX2 not detected; using baseline build."
+fi
+
+BINARY="bunny-${OS}-${ARCH}${VARIANT}"
 
 # Pinned version uses the tagged release URL; otherwise use the `latest`
 # redirect so we don't hit api.github.com (rate-limited to 60 req/hr).
diff --git a/packages/cli-darwin-x64/package.json b/packages/cli-darwin-x64/package.json
index aceba7d..8a65b3f 100644
--- a/packages/cli-darwin-x64/package.json
+++ b/packages/cli-darwin-x64/package.json
@@ -9,7 +9,8 @@
     "x64"
   ],
   "files": [
-    "bunny"
+    "bunny",
+    "bunny-baseline"
   ],
   "publishConfig": {
     "access": "public"
diff --git a/packages/cli-linux-x64/package.json b/packages/cli-linux-x64/package.json
index 04d7f67..cb0b10b 100644
--- a/packages/cli-linux-x64/package.json
+++ b/packages/cli-linux-x64/package.json
@@ -9,7 +9,8 @@
     "x64"
   ],
   "files": [
-    "bunny"
+    "bunny",
+    "bunny-baseline"
   ],
   "publishConfig": {
     "access": "public"
diff --git a/packages/cli/bin/bunny.cjs b/packages/cli/bin/bunny.cjs
index 6e53b3a..3b70a86 100755
--- a/packages/cli/bin/bunny.cjs
+++ b/packages/cli/bin/bunny.cjs
@@ -1,9 +1,30 @@
 #!/usr/bin/env node
 
 const { execFileSync } = require("node:child_process");
-const { existsSync } = require("node:fs");
+const { existsSync, readFileSync } = require("node:fs");
 const path = require("node:path");
 
+// Only x64 binaries use AVX2; assume it's present on other arches or when detection fails, letting the SIGILL fallback catch any mistake.
+function hasAvx2() {
+  if (process.arch !== "x64") return true;
+  try {
+    if (process.platform === "linux") {
+      return readFileSync("/proc/cpuinfo", "utf8").includes("avx2");
+    }
+    if (process.platform === "darwin") {
+      const features = execFileSync(
+        "sysctl",
+        ["-n", "machdep.cpu.leaf7_features"],
+        { encoding: "utf8" },
+      );
+      return /avx2/i.test(features);
+    }
+  } catch {
+    return true;
+  }
+  return true;
+}
+
 const PLATFORMS = {
   "darwin-arm64": "@bunny.net/cli-darwin-arm64",
   "darwin-x64": "@bunny.net/cli-darwin-x64",
@@ -45,12 +66,35 @@ if (!existsSync(binPath)) {
   process.exit(1);
 }
 
-try {
-  execFileSync(binPath, process.argv.slice(2), { stdio: "inherit" });
-} catch (err) {
-  if (err.status != null) {
-    process.exit(err.status);
+// The default binary uses AVX2; on pre-Haswell x64 CPUs it dies with SIGILL, so fall back to the baseline build shipped alongside it.
+const baselinePath = path.join(path.dirname(binPath), "bunny-baseline");
+const candidates = [binPath];
+if (existsSync(baselinePath)) {
+  candidates.push(baselinePath);
+}
+// Run the baseline first on x64 CPUs without AVX2, so we don't spawn the default binary just to catch its crash on every invocation.
+if (candidates.length > 1 && !hasAvx2()) {
+  candidates.reverse();
+}
+
+for (let i = 0; i < candidates.length; i++) {
+  try {
+    execFileSync(candidates[i], process.argv.slice(2), { stdio: "inherit" });
+    process.exit(0);
+  } catch (err) {
+    if (err.status != null) {
+      process.exit(err.status);
+    }
+    if (err.signal === "SIGILL" && i < candidates.length - 1) {
+      continue;
+    }
+    if (err.signal === "SIGILL") {
+      console.error(
+        "bunny crashed with an illegal instruction; this CPU is not supported.",
+      );
+      process.exit(1);
+    }
+    console.error(`Failed to execute bunny binary: ${err.message}`);
+    process.exit(1);
   }
-  console.error(`Failed to execute bunny binary: ${err.message}`);
-  process.exit(1);
 }
diff --git a/packages/database-shell-darwin-x64/package.json b/packages/database-shell-darwin-x64/package.json
index d9cc641..7c2f799 100644
--- a/packages/database-shell-darwin-x64/package.json
+++ b/packages/database-shell-darwin-x64/package.json
@@ -9,7 +9,8 @@
     "x64"
   ],
   "files": [
-    "bsql"
+    "bsql",
+    "bsql-baseline"
   ],
   "publishConfig": {
     "access": "public"
diff --git a/packages/database-shell-linux-x64/package.json b/packages/database-shell-linux-x64/package.json
index 5a7a06b..6b2be30 100644
--- a/packages/database-shell-linux-x64/package.json
+++ b/packages/database-shell-linux-x64/package.json
@@ -9,7 +9,8 @@
     "x64"
   ],
   "files": [
-    "bsql"
+    "bsql",
+    "bsql-baseline"
   ],
   "publishConfig": {
     "access": "public"
diff --git a/packages/database-shell/bin/bsql.cjs b/packages/database-shell/bin/bsql.cjs
index 93c8db8..cddd724 100755
--- a/packages/database-shell/bin/bsql.cjs
+++ b/packages/database-shell/bin/bsql.cjs
@@ -1,9 +1,30 @@
 #!/usr/bin/env node
 
 const { execFileSync } = require("node:child_process");
-const { existsSync } = require("node:fs");
+const { existsSync, readFileSync } = require("node:fs");
 const path = require("node:path");
 
+// Only x64 binaries use AVX2; assume it's present on other arches or when detection fails, letting the SIGILL fallback catch any mistake.
+function hasAvx2() {
+  if (process.arch !== "x64") return true;
+  try {
+    if (process.platform === "linux") {
+      return readFileSync("/proc/cpuinfo", "utf8").includes("avx2");
+    }
+    if (process.platform === "darwin") {
+      const features = execFileSync(
+        "sysctl",
+        ["-n", "machdep.cpu.leaf7_features"],
+        { encoding: "utf8" },
+      );
+      return /avx2/i.test(features);
+    }
+  } catch {
+    return true;
+  }
+  return true;
+}
+
 const PLATFORMS = {
   "darwin-arm64": "@bunny.net/database-shell-darwin-arm64",
   "darwin-x64": "@bunny.net/database-shell-darwin-x64",
@@ -45,12 +66,35 @@ if (!existsSync(binPath)) {
   process.exit(1);
 }
 
-try {
-  execFileSync(binPath, process.argv.slice(2), { stdio: "inherit" });
-} catch (err) {
-  if (err.status != null) {
-    process.exit(err.status);
+// The default binary uses AVX2; on pre-Haswell x64 CPUs it dies with SIGILL, so fall back to the baseline build shipped alongside it.
+const baselinePath = path.join(path.dirname(binPath), "bsql-baseline");
+const candidates = [binPath];
+if (existsSync(baselinePath)) {
+  candidates.push(baselinePath);
+}
+// Run the baseline first on x64 CPUs without AVX2, so we don't spawn the default binary just to catch its crash on every invocation.
+if (candidates.length > 1 && !hasAvx2()) {
+  candidates.reverse();
+}
+
+for (let i = 0; i < candidates.length; i++) {
+  try {
+    execFileSync(candidates[i], process.argv.slice(2), { stdio: "inherit" });
+    process.exit(0);
+  } catch (err) {
+    if (err.status != null) {
+      process.exit(err.status);
+    }
+    if (err.signal === "SIGILL" && i < candidates.length - 1) {
+      continue;
+    }
+    if (err.signal === "SIGILL") {
+      console.error(
+        "bsql crashed with an illegal instruction; this CPU is not supported.",
+      );
+      process.exit(1);
+    }
+    console.error(`Failed to execute bsql binary: ${err.message}`);
+    process.exit(1);
   }
-  console.error(`Failed to execute bsql binary: ${err.message}`);
-  process.exit(1);
 }