diff --git a/src/lib/actions/uninstall/run-plan.test.ts b/src/lib/actions/uninstall/run-plan.test.ts
index 72b3d2fd92f..03091864b16 100644
--- a/src/lib/actions/uninstall/run-plan.test.ts
+++ b/src/lib/actions/uninstall/run-plan.test.ts
@@ -582,4 +582,41 @@ describe("uninstall run plan", () => {
     expect(warnings).toContain("Failed to disable /swapfile; skipping swap cleanup.");
     expect(logs).not.toContain("Swap file removed");
   });
+
+  it("#3456 sub-bug #4: gateway destroy no-op uses the 'already removed' wording, not 'Destroyed ... skipped'", () => {
+    // When `openshell gateway destroy -g nemoclaw` returns non-zero (gateway
+    // already gone), the previous code printed `Destroyed gateway 'nemoclaw'
+    // skipped` — self-contradictory. The fix routes this branch to an onSkip
+    // message that describes the actual state.
+    const warnings: string[] = [];
+    const logs: string[] = [];
+    const result = runUninstallPlan(
+      { assumeYes: true, deleteModels: false, keepOpenShell: true },
+      {
+        commandExists: (command) => command !== "docker" && command !== "pgrep",
+        env: { HOME: "/home/test", TMPDIR: "/tmp/test" } as NodeJS.ProcessEnv,
+        error: (line) => warnings.push(line),
+        existsSync: () => false,
+        isTty: false,
+        log: (line) => logs.push(line),
+        rmSync: vi.fn(),
+        run: (command, args) => {
+          // The openshell gateway destroy command no-ops when the gateway is
+          // already gone — return non-zero to exercise the onSkip branch.
+          if (command === "openshell" && args[0] === "gateway" && args[1] === "destroy") {
+            return notFound();
+          }
+          if (args[0] === "-c") return ok("/fake/bin/tool\n");
+          return ok();
+        },
+        runDocker: () => ok(""),
+      },
+    );
+
+    expect(result.exitCode).toBe(0);
+    expect(warnings.join("\n")).toContain("Gateway 'nemoclaw' already removed or unreachable");
+    expect(`${warnings.join("\n")}\n${logs.join("\n")}`).not.toContain(
+      "Destroyed gateway 'nemoclaw' skipped",
+    );
+  });
 });
diff --git a/src/lib/actions/uninstall/run-plan.ts b/src/lib/actions/uninstall/run-plan.ts
index b3d71ea1fc3..c99289bbebe 100644
--- a/src/lib/actions/uninstall/run-plan.ts
+++ b/src/lib/actions/uninstall/run-plan.ts
@@ -207,10 +207,24 @@ function confirm(options: UninstallRunOptions, runtime: UninstallRuntime): boole
   return false;
 }
 
-function runOptional(runtime: UninstallRuntime, description: string, command: string, args: string[]): void {
+function runOptional(
+  runtime: UninstallRuntime,
+  description: string,
+  command: string,
+  args: string[],
+  opts: { onSkip?: string } = {},
+): void {
   const result = runtime.run(command, args, { env: runtime.env, stdio: "ignore" });
-  if (result.status === 0) runtime.log(description);
-  else runtime.warn(`${description} skipped`);
+  if (result.status === 0) {
+    runtime.log(description);
+    return;
+  }
+  // #3456 sub-bug #4: when the destroy/delete call no-ops (target already
+  // gone), printing `<description> skipped` was self-contradictory — e.g.
+  // "Destroyed gateway 'nemoclaw' skipped" suggested the gateway was both
+  // destroyed AND skipped. Callers that care can pass a `onSkip` message
+  // describing the actual state (target absent or unreachable).
+  runtime.warn(opts.onSkip ?? `${description} skipped`);
 }
 
 function stopHelperServices(paths: UninstallPaths, runtime: UninstallRuntime): void {
@@ -390,12 +404,14 @@ function removeOpenShellResources(options: UninstallRunOptions, runtime: Uninsta
   for (const provider of NEMOCLAW_PROVIDERS) {
     runOptional(runtime, `Deleted provider '${provider}'`, "openshell", ["provider", "delete", provider]);
   }
-  runOptional(runtime, `Destroyed gateway '${options.gatewayName || "nemoclaw"}'`, "openshell", [
-    "gateway",
-    "destroy",
-    "-g",
-    options.gatewayName || "nemoclaw",
-  ]);
+  const gatewayLabel = options.gatewayName || "nemoclaw";
+  runOptional(
+    runtime,
+    `Destroyed gateway '${gatewayLabel}'`,
+    "openshell",
+    ["gateway", "destroy", "-g", gatewayLabel],
+    { onSkip: `Gateway '${gatewayLabel}' already removed or unreachable` },
+  );
 }
 
 function removeAliases(paths: UninstallPaths, runtime: UninstallRuntime): void {
diff --git a/src/lib/onboard.ts b/src/lib/onboard.ts
index 104359340fb..f33a1cdf3ba 100644
--- a/src/lib/onboard.ts
+++ b/src/lib/onboard.ts
@@ -343,6 +343,7 @@ import type {
 } from "./onboard/types";
 import { listChannels } from "./sandbox/channels";
 import { streamGatewayStart } from "./onboard/gateway";
+import { reportGpuPassthroughRecovery } from "./onboard/gpu-recovery";
 import type { StreamSandboxCreateResult } from "./sandbox/create-stream";
 import type { SandboxEntry } from "./state/registry";
 import type { BackupResult } from "./state/sandbox";
@@ -10343,9 +10344,7 @@ async function onboard(opts: OnboardOptions = {}): Promise<void> {
       const gpuOutput = String(gpuCheck.stdout || "").trim();
       const gatewayHasGpu = gpuCheck.status === 0 && gpuOutput !== "null" && gpuOutput !== "[]";
       if (!gatewayHasGpu) {
-        console.error("  Existing gateway was started without GPU passthrough.");
-        console.error("  To enable GPU, destroy the existing sandbox and gateway, then re-onboard:");
-        console.error(`    nemoclaw <name> destroy --yes && nemoclaw onboard --gpu`);
+        reportGpuPassthroughRecovery(console.error);
         process.exit(1);
       }
     }
diff --git a/src/lib/onboard/gpu-recovery.test.ts b/src/lib/onboard/gpu-recovery.test.ts
new file mode 100644
index 00000000000..172501e63cc
--- /dev/null
+++ b/src/lib/onboard/gpu-recovery.test.ts
@@ -0,0 +1,92 @@
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+/**
+ * Tests for the GPU-passthrough mismatch recovery hint (#3456 sub-bug #3).
+ *
+ * The hint replaces a hard-coded line that printed a literal `<name>`
+ * placeholder and assumed at least one sandbox was registered — which broke
+ * the install-loop recovery flow when the registry was empty (the State A /
+ * State B dead loop the reporter hit on six Linux hosts).
+ */
+
+import { describe, expect, it, vi } from "vitest";
+import { gpuPassthroughRecoveryLines, reportGpuPassthroughRecovery } from "./gpu-recovery";
+
+describe("gpuPassthroughRecoveryLines", () => {
+  it("never emits a literal `<name>` placeholder for any input", () => {
+    for (const names of [null, [], ["alpha"], ["alpha", "beta"], ["alpha", "beta", "gamma"]]) {
+      const lines = gpuPassthroughRecoveryLines(names);
+      expect(lines.join("\n")).not.toMatch(/<name>/);
+    }
+  });
+
+  it("suggests `nemoclaw uninstall` when no sandboxes are registered (null input)", () => {
+    const lines = gpuPassthroughRecoveryLines(null);
+    const joined = lines.join("\n");
+    expect(joined).toContain("Existing gateway was started without GPU passthrough");
+    expect(joined).toContain("nemoclaw uninstall");
+    expect(joined).toContain("nemoclaw onboard --gpu");
+    // Must NOT suggest the destroy form — there is nothing to destroy.
+    expect(joined).not.toMatch(/nemoclaw [a-z-]+ destroy/);
+  });
+
+  it("suggests `nemoclaw uninstall` when no sandboxes are registered (empty array)", () => {
+    const lines = gpuPassthroughRecoveryLines([]);
+    expect(lines.join("\n")).toContain("nemoclaw uninstall");
+    expect(lines.join("\n")).not.toMatch(/nemoclaw [a-z-]+ destroy/);
+  });
+
+  it("suggests destroy for a single registered sandbox with --cleanup-gateway", () => {
+    const lines = gpuPassthroughRecoveryLines(["my-assistant"]);
+    const joined = lines.join("\n");
+    expect(joined).toContain("nemoclaw my-assistant destroy --yes --cleanup-gateway");
+    expect(joined).toContain("nemoclaw onboard --gpu");
+    // The single-sandbox form must not suggest uninstall — destroy is enough.
+    expect(joined).not.toContain("nemoclaw uninstall");
+  });
+
+  it("lists every registered sandbox and only appends --cleanup-gateway to the last", () => {
+    const lines = gpuPassthroughRecoveryLines(["alpha", "beta", "gamma"]);
+    const joined = lines.join("\n");
+    expect(joined).toContain("nemoclaw alpha destroy --yes");
+    expect(joined).toContain("nemoclaw beta destroy --yes");
+    expect(joined).toContain("nemoclaw gamma destroy --yes --cleanup-gateway");
+    // Only one --cleanup-gateway across all rows.
+    expect(joined.match(/--cleanup-gateway/g) ?? []).toHaveLength(1);
+    // alpha/beta lines must NOT have --cleanup-gateway.
+    const alphaLine = lines.find((line) => line.includes("nemoclaw alpha destroy"));
+    const betaLine = lines.find((line) => line.includes("nemoclaw beta destroy"));
+    expect(alphaLine).not.toContain("--cleanup-gateway");
+    expect(betaLine).not.toContain("--cleanup-gateway");
+  });
+
+  it("filters out empty/whitespace names defensively", () => {
+    // Belt-and-suspenders: if registry.listSandboxes() ever returns a row with
+    // an empty name, we shouldn't render `nemoclaw  destroy --yes` (the very
+    // bug shape this fix exists to prevent).
+    const lines = gpuPassthroughRecoveryLines(["", "  ", "real"]);
+    const joined = lines.join("\n");
+    expect(joined).toContain("nemoclaw real destroy --yes --cleanup-gateway");
+    // No double-spaced "nemoclaw  destroy" rendering.
+    expect(joined).not.toMatch(/nemoclaw\s{2,}destroy/);
+  });
+});
+
+describe("reportGpuPassthroughRecovery", () => {
+  it("emits the empty-registry path when loadNames returns no names", () => {
+    const emit = vi.fn();
+    reportGpuPassthroughRecovery(emit, () => []);
+    const joined = emit.mock.calls.map((c) => c[0]).join("\n");
+    expect(joined).toContain("nemoclaw uninstall");
+    expect(joined).not.toMatch(/<name>/);
+  });
+
+  it("emits the multi-sandbox path when loadNames returns several names", () => {
+    const emit = vi.fn();
+    reportGpuPassthroughRecovery(emit, () => ["alpha", "beta"]);
+    const joined = emit.mock.calls.map((c) => c[0]).join("\n");
+    expect(joined).toContain("nemoclaw alpha destroy --yes");
+    expect(joined).toContain("nemoclaw beta destroy --yes --cleanup-gateway");
+  });
+});
diff --git a/src/lib/onboard/gpu-recovery.ts b/src/lib/onboard/gpu-recovery.ts
new file mode 100644
index 00000000000..51c770adf4b
--- /dev/null
+++ b/src/lib/onboard/gpu-recovery.ts
@@ -0,0 +1,91 @@
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+/**
+ * Recovery hint emitted when an onboard run finds the reusable gateway was
+ * started without GPU passthrough but the current run requested it.
+ *
+ * Before #3456 this was a hard-coded `nemoclaw <name> destroy --yes` line
+ * with a literal `<name>` placeholder — not actionable when the registry was
+ * empty (the State A / State B dead loop the reporter hit on six Linux
+ * hosts). This helper renders the right shape based on what's actually
+ * registered AND owns the registry lookup, so the onboard.ts callsite stays
+ * a single call (also keeps onboard.ts inside its size budget).
+ */
+
+import * as registry from "../state/registry";
+
+/**
+ * Returns the multi-line recovery hint for the GPU-passthrough mismatch
+ * branch in onboard. Caller is expected to emit each line on its own line
+ * via `console.error` / `runtime.log`.
+ *
+ * Empty / null input means no sandboxes are registered locally; we suggest
+ * `nemoclaw uninstall` because there is nothing for `nemoclaw <name>
+ * destroy` to act on. A single registered sandbox gets one destroy line
+ * with `--cleanup-gateway` so the gateway also goes away (otherwise destroy
+ * preserves the shared gateway by default — see v0.0.39 release notes).
+ * Multiple sandboxes get one destroy line each; only the last carries
+ * `--cleanup-gateway` so the gateway lives until every sandbox is gone.
+ */
+export function gpuPassthroughRecoveryLines(names: readonly string[] | null): string[] {
+  const cleanNames = (names ?? []).map((n) => n.trim()).filter((n) => n.length > 0);
+
+  if (cleanNames.length === 0) {
+    return [
+      "  Existing gateway was started without GPU passthrough.",
+      "  No sandboxes are registered, so there is nothing for `nemoclaw destroy` to act on.",
+      "  Clear the stale gateway state and re-onboard with GPU enabled:",
+      "    nemoclaw uninstall && nemoclaw onboard --gpu",
+    ];
+  }
+
+  if (cleanNames.length === 1) {
+    return [
+      "  Existing gateway was started without GPU passthrough.",
+      "  To enable GPU, destroy the existing sandbox and gateway, then re-onboard:",
+      `    nemoclaw ${cleanNames[0]} destroy --yes --cleanup-gateway && nemoclaw onboard --gpu`,
+    ];
+  }
+
+  const lastIdx = cleanNames.length - 1;
+  const destroyLines = cleanNames.map((name, idx) =>
+    idx === lastIdx
+      ? `    nemoclaw ${name} destroy --yes --cleanup-gateway && nemoclaw onboard --gpu`
+      : `    nemoclaw ${name} destroy --yes`,
+  );
+
+  return [
+    "  Existing gateway was started without GPU passthrough.",
+    "  To enable GPU, destroy each registered sandbox and the gateway, then re-onboard:",
+    ...destroyLines,
+  ];
+}
+
+/**
+ * Read registered sandbox names with a graceful empty-list fallback when the
+ * registry can't be opened. Extracted so the onboard callsite stays a single
+ * line and so unit tests can inject their own list.
+ */
+export function getRegisteredSandboxNamesForGpuRecovery(): string[] {
+  try {
+    return registry
+      .listSandboxes()
+      .sandboxes.map((s) => s.name)
+      .filter(Boolean);
+  } catch {
+    return [];
+  }
+}
+
+/**
+ * Emit the GPU-passthrough mismatch recovery hint to `emit` (typically
+ * `console.error`). `loadNames` is injectable for tests; the production
+ * default reads the on-disk sandbox registry.
+ */
+export function reportGpuPassthroughRecovery(
+  emit: (line: string) => void,
+  loadNames: () => string[] = getRegisteredSandboxNamesForGpuRecovery,
+): void {
+  for (const line of gpuPassthroughRecoveryLines(loadNames())) emit(line);
+}