diff --git a/src/lib/actions/sandbox/rebuild-credential-preflight.ts b/src/lib/actions/sandbox/rebuild-credential-preflight.ts
index e4359d25be8..0576b155611 100644
--- a/src/lib/actions/sandbox/rebuild-credential-preflight.ts
+++ b/src/lib/actions/sandbox/rebuild-credential-preflight.ts
@@ -145,6 +145,7 @@ export function preflightRebuildCredentials(
   sb: RebuildSandboxEntry,
   log: RebuildLog,
   bail: RebuildBail,
+  options: { allowMissingGatewayProviderWithHostCredential?: boolean } = {},
 ): boolean {
   const rebuildCredentialEnv = getRebuildCredentialEnvFromRegistry(sb.provider, sb.credentialEnv);
   const rebuildProvider = sb.provider;
@@ -171,7 +172,12 @@ export function preflightRebuildCredentials(
   log(
     `Preflight credential check: ${rebuildCredentialEnv} → ${credentialValue ? "present" : "MISSING"}`,
   );
-  if (!checkRebuildGatewayProviderOrBail(rebuildProvider, rebuildCredentialEnv, log, bail)) {
+  if (
+    !checkRebuildGatewayProviderOrBail(rebuildProvider, rebuildCredentialEnv, log, bail, {
+      allowMissingProvider:
+        options.allowMissingGatewayProviderWithHostCredential === true && Boolean(credentialValue),
+    })
+  ) {
     return false;
   }
   if (!credentialValue && shouldVerifyRebuildGatewayProvider(rebuildProvider)) {
diff --git a/src/lib/actions/sandbox/rebuild-onboard-dependencies.ts b/src/lib/actions/sandbox/rebuild-onboard-dependencies.ts
index 917243a729d..392cdacc186 100644
--- a/src/lib/actions/sandbox/rebuild-onboard-dependencies.ts
+++ b/src/lib/actions/sandbox/rebuild-onboard-dependencies.ts
@@ -5,6 +5,7 @@ import type { RebuildDurableConfig } from "./rebuild-durable-config";
 import type { RebuildRecreateOnboardOpts } from "./rebuild-gpu-opt-out";
 
 type RebuildAuthoritativePreflightOptions = RebuildRecreateOnboardOpts & {
+  deferInferenceRouteUntilOnboard?: true;
   model: string;
   provider: string;
   sandboxName: string;
diff --git a/src/lib/actions/sandbox/rebuild-preflight-phase.ts b/src/lib/actions/sandbox/rebuild-preflight-phase.ts
index e95a3889e63..08a41c3e547 100644
--- a/src/lib/actions/sandbox/rebuild-preflight-phase.ts
+++ b/src/lib/actions/sandbox/rebuild-preflight-phase.ts
@@ -140,6 +140,7 @@ export async function runRebuildPreflightPhase(
         // succeeded, matching the previous `skipConfirm || confirmed` contract.
         autoYes: true,
         requestedToolDisclosure,
+        preparedBackupRecovery: recoveryManifest !== null,
         log,
         bail,
       });
diff --git a/src/lib/actions/sandbox/rebuild-preflight-target-phase.ts b/src/lib/actions/sandbox/rebuild-preflight-target-phase.ts
index b43b3bf4a43..1bbf3b5a15c 100644
--- a/src/lib/actions/sandbox/rebuild-preflight-target-phase.ts
+++ b/src/lib/actions/sandbox/rebuild-preflight-target-phase.ts
@@ -49,11 +49,20 @@ export async function prepareRebuildTargetPreflights(args: {
   rebuildAgent: string | null;
   autoYes: boolean;
   requestedToolDisclosure?: ToolDisclosure;
+  preparedBackupRecovery?: boolean;
   log: RebuildLog;
   bail: RebuildBail;
 }): Promise<RebuildPreparedTarget | null> {
-  const { sandboxName, sandboxEntry, rebuildAgent, autoYes, requestedToolDisclosure, log, bail } =
-    args;
+  const {
+    sandboxName,
+    sandboxEntry,
+    rebuildAgent,
+    autoYes,
+    requestedToolDisclosure,
+    preparedBackupRecovery,
+    log,
+    bail,
+  } = args;
   hydrateMessagingConfigForRebuild(sandboxName, log);
   if (!(await ensureRebuildTargetGatewaySelected(sandboxName, sandboxEntry, log, bail)))
     return null;
@@ -115,7 +124,13 @@ export async function prepareRebuildTargetPreflights(args: {
     bail,
   });
   if (
-    !(await preflightAuthoritativeOnboardRuntime(sandboxName, resumeConfig, recreateOptions, bail))
+    !(await preflightAuthoritativeOnboardRuntime(
+      sandboxName,
+      resumeConfig,
+      recreateOptions,
+      bail,
+      preparedBackupRecovery ? { deferInferenceRouteUntilOnboard: true } : {},
+    ))
   ) {
     return null;
   }
@@ -142,7 +157,10 @@ export async function prepareRebuildTargetPreflights(args: {
       recreateOptions,
       log,
       bail,
-      { skipImagePreflight: rebuildsDcodeSandbox },
+      {
+        allowMissingGatewayProviderWithHostCredential: preparedBackupRecovery,
+        skipImagePreflight: rebuildsDcodeSandbox,
+      },
     );
   } finally {
     restoreBaseImageOverride();
diff --git a/src/lib/actions/sandbox/rebuild-prepared-recovery.test.ts b/src/lib/actions/sandbox/rebuild-prepared-recovery.test.ts
index fd5851e2449..65dc481bc9d 100644
--- a/src/lib/actions/sandbox/rebuild-prepared-recovery.test.ts
+++ b/src/lib/actions/sandbox/rebuild-prepared-recovery.test.ts
@@ -37,6 +37,9 @@ describe("prepared rebuild recovery", () => {
     ).resolves.toBeUndefined();
 
     expect(harness.backupSandboxStateSpy).not.toHaveBeenCalled();
+    expect(harness.preflightAuthoritativeRebuildTargetSpy).toHaveBeenCalledWith(
+      expect.objectContaining({ deferInferenceRouteUntilOnboard: true }),
+    );
     expect(harness.runOpenshellSpy).toHaveBeenCalledWith(
       ["sandbox", "delete", "alpha"],
       expect.objectContaining({ ignoreError: true }),
diff --git a/src/lib/actions/sandbox/rebuild-provider-preflight.ts b/src/lib/actions/sandbox/rebuild-provider-preflight.ts
index 0bea1e6df54..f8fde74a5cb 100644
--- a/src/lib/actions/sandbox/rebuild-provider-preflight.ts
+++ b/src/lib/actions/sandbox/rebuild-provider-preflight.ts
@@ -76,6 +76,7 @@ export function checkRebuildGatewayProviderOrBail(
   credentialEnv: string | null,
   log: (msg: string) => void,
   bail: (msg: string, code?: number) => never,
+  options: { allowMissingProvider?: boolean } = {},
 ): boolean {
   if (!shouldVerifyRebuildGatewayProvider(provider)) return true;
 
@@ -86,6 +87,12 @@ export function checkRebuildGatewayProviderOrBail(
     } in OpenShell`,
   );
   if (providerRegisteredInGateway) return true;
+  if (options.allowMissingProvider) {
+    log(
+      `Preflight gateway provider check: prepared recovery will recreate missing provider '${provider}' from its explicit host credential`,
+    );
+    return true;
+  }
 
   printMissingRebuildGatewayProvider(provider, credentialEnv);
   bail(`Missing gateway provider: ${provider}`);
diff --git a/src/lib/actions/sandbox/rebuild-target-runtime.ts b/src/lib/actions/sandbox/rebuild-target-runtime.ts
index 07182aa3e5f..c713b754d87 100644
--- a/src/lib/actions/sandbox/rebuild-target-runtime.ts
+++ b/src/lib/actions/sandbox/rebuild-target-runtime.ts
@@ -67,7 +67,10 @@ export async function preflightRebuildTargetRuntime(
   recreateOptions: RebuildRecreateOnboardOpts,
   log: RebuildLog,
   bail: RebuildBail,
-  options: { skipImagePreflight?: boolean } = {},
+  options: {
+    allowMissingGatewayProviderWithHostCredential?: boolean;
+    skipImagePreflight?: boolean;
+  } = {},
 ): Promise<RebuildTargetRuntimePreflightResult> {
   const webSearchConfig = target.durableConfig.webSearchConfig;
   const webSearchProvider = webSearchConfig ? webSearchProviderForConfig(webSearchConfig) : null;
@@ -186,6 +189,10 @@ export async function preflightRebuildTargetRuntime(
         },
         log,
         bail,
+        {
+          allowMissingGatewayProviderWithHostCredential:
+            options.allowMissingGatewayProviderWithHostCredential,
+        },
       )
     ) {
       return { ok: false };
@@ -203,10 +210,12 @@ export async function preflightAuthoritativeOnboardRuntime(
   resumeConfig: RebuildResumeConfig,
   recreateOptions: RebuildRecreateOnboardOpts,
   bail: RebuildBail,
+  options: { deferInferenceRouteUntilOnboard?: true } = {},
 ): Promise<boolean> {
   try {
     await rebuildOnboardDependencies.preflightAuthoritativeRebuildTarget({
       ...recreateOptions,
+      ...options,
       model: resumeConfig.model,
       provider: resumeConfig.provider,
       sandboxName,
diff --git a/src/lib/onboard/authoritative-rebuild-target.test.ts b/src/lib/onboard/authoritative-rebuild-target.test.ts
index a078d7dfc7c..c715c05b2e3 100644
--- a/src/lib/onboard/authoritative-rebuild-target.test.ts
+++ b/src/lib/onboard/authoritative-rebuild-target.test.ts
@@ -121,6 +121,21 @@ describe("authoritative rebuild target preflight", () => {
     ).rejects.toThrow("inference route does not match");
   });
 
+  it("defers route validation for prepared recovery until authoritative onboard", async () => {
+    const targetDeps = deps({ inferenceRouteReady: vi.fn(() => false) });
+
+    await expect(
+      preflightAuthoritativeRebuildTarget(
+        { ...target, deferInferenceRouteUntilOnboard: true },
+        targetDeps,
+      ),
+    ).resolves.toBeUndefined();
+
+    expect(targetDeps.inferenceRouteReady).not.toHaveBeenCalled();
+    expect(targetDeps.runFatalRuntimePreflight).toHaveBeenCalledOnce();
+    expect(targetDeps.ensureOpenshell).toHaveBeenCalledOnce();
+  });
+
   it("rejects a dashboard forward owned by another sandbox", async () => {
     await expect(
       preflightAuthoritativeRebuildTarget(
diff --git a/src/lib/onboard/authoritative-rebuild-target.ts b/src/lib/onboard/authoritative-rebuild-target.ts
index b8b01f37bbf..c6f0fac70bc 100644
--- a/src/lib/onboard/authoritative-rebuild-target.ts
+++ b/src/lib/onboard/authoritative-rebuild-target.ts
@@ -19,6 +19,7 @@ export type AuthoritativeRebuildPreflightOptions = Pick<
   "sandboxGpu" | "sandboxGpuDevice" | "noGpu" | "controlUiPort"
 > & {
   authoritativeResumeConfig: true;
+  deferInferenceRouteUntilOnboard?: true;
   model: string;
   provider: string;
   sandboxName: string;
@@ -60,6 +61,7 @@ export function resolveAuthoritativeOnboardGatewayBinding(
 }
 
 export type AuthoritativeRebuildTarget = {
+  deferInferenceRouteUntilOnboard?: true;
   sandboxName: string;
   provider: string;
   model: string;
@@ -90,7 +92,14 @@ export async function preflightAuthoritativeRebuildTarget(
   try {
     deps.runFatalRuntimePreflight();
     deps.ensureOpenshell();
-    if (!deps.inferenceRouteReady(target.provider, target.model)) {
+    // Prepared-backup recovery can run after the installer has replaced a
+    // legacy gateway. That fresh gateway has no inference route to validate
+    // yet; authoritative onboarding configures and verifies the pinned route
+    // before recreating the sandbox. Normal rebuilds must still match here.
+    if (
+      target.deferInferenceRouteUntilOnboard !== true &&
+      !deps.inferenceRouteReady(target.provider, target.model)
+    ) {
       fail(
         `OpenShell inference route does not match provider '${target.provider}' and model '${target.model}'.`,
       );
diff --git a/test/helpers/rebuild-flow-credential-preflight-cases.ts b/test/helpers/rebuild-flow-credential-preflight-cases.ts
index 0e1be8931ae..23d8cdcf186 100644
--- a/test/helpers/rebuild-flow-credential-preflight-cases.ts
+++ b/test/helpers/rebuild-flow-credential-preflight-cases.ts
@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import { describe, expect, it } from "vitest";
+import { makePreparedRecoveryManifest } from "../../src/lib/actions/sandbox/rebuild-flow-test-fixtures";
 import { createRebuildFlowHarness, installRebuildFlowTestHooks } from "./rebuild-flow-test-harness";
 
 type Harness = ReturnType<typeof createRebuildFlowHarness>;
@@ -150,6 +151,37 @@ export function registerRebuildFlowCredentialPreflightTests(): void {
       expect(harness.backupSandboxStateSpy).not.toHaveBeenCalled();
     });
 
+    it("recreates a missing provider from an explicit host credential during prepared recovery", async () => {
+      const harness = createRebuildFlowHarness({
+        sandboxEntry: {
+          provider: "compatible-endpoint",
+          model: MODEL,
+          credentialEnv: "COMPATIBLE_API_KEY",
+          endpointUrl: "https://inference.example.test/v1",
+        },
+        hydrateCredentialEnv: () => "host-provider-key",
+        runOpenshell: providerRuntime([]),
+        sandboxListOutput: "alpha Error",
+      });
+      configureSession(harness, "compatible-endpoint", "COMPATIBLE_API_KEY", {
+        endpointUrl: "https://inference.example.test/v1",
+      });
+
+      await expect(
+        harness.rebuildSandbox("alpha", ["--yes"], {
+          throwOnError: true,
+          recoveryManifest: makePreparedRecoveryManifest(),
+        }),
+      ).resolves.toBeUndefined();
+
+      expect(harness.backupSandboxStateSpy).not.toHaveBeenCalled();
+      expect(harness.onboardSpy).toHaveBeenCalledOnce();
+      expect(harness.runOpenshellSpy).toHaveBeenCalledWith(
+        ["provider", "get", "compatible-endpoint"],
+        expect.anything(),
+      );
+    });
+
     it("copies the staged Hermes messaging plan into the rebuild resume session", async () => {
       const plan = makeMessagingPlan();
       const harness = createRebuildFlowHarness({
diff --git a/test/helpers/rebuild-flow-harness.ts b/test/helpers/rebuild-flow-harness.ts
index 16324a73e1c..9644bfd6a21 100644
--- a/test/helpers/rebuild-flow-harness.ts
+++ b/test/helpers/rebuild-flow-harness.ts
@@ -133,6 +133,7 @@ export type RebuildFlowHarness = {
   markStepFailedSpy: MockInstance;
   openShieldsSpy: MockInstance;
   onboardSpy: MockInstance;
+  preflightAuthoritativeRebuildTargetSpy: MockInstance;
   preflightMessagingConflictsSpy: MockInstance;
   preflightDcodeRouteSpy: MockInstance;
   prepareManagedDcodeRebuildImageSpy: MockInstance;
@@ -484,9 +485,9 @@ export function createRebuildFlowHarness(overrides: RebuildFlowOverrides = {}):
   vi.spyOn(rebuildOnboardDependencies, "hydrateCredentialEnv").mockImplementation(
     (...args: unknown[]) => onboardCredentialEnv.hydrateCredentialEnv(String(args[0] ?? "")),
   );
-  vi.spyOn(rebuildOnboardDependencies, "preflightAuthoritativeRebuildTarget").mockResolvedValue(
-    undefined,
-  );
+  const preflightAuthoritativeRebuildTargetSpy = vi
+    .spyOn(rebuildOnboardDependencies, "preflightAuthoritativeRebuildTarget")
+    .mockResolvedValue(undefined);
   const applyPresetSpy = vi
     .spyOn(policies, "applyPreset")
     .mockImplementation((_sandboxName: unknown, presetName: unknown) => {
@@ -556,6 +557,7 @@ export function createRebuildFlowHarness(overrides: RebuildFlowOverrides = {}):
     markStepFailedSpy,
     openShieldsSpy,
     onboardSpy,
+    preflightAuthoritativeRebuildTargetSpy,
     preflightMessagingConflictsSpy,
     preflightDcodeRouteSpy,
     prepareManagedDcodeRebuildImageSpy,