maralcbr · Oct 4, 2026 · Oct 4, 2026 · Oct 4, 2026 · Oct 4, 2026 · Oct 4, 2026
diff --git a/Engine/overlay/src/omarchy_runtime.py b/Engine/overlay/src/omarchy_runtime.py
@@ -154,14 +154,15 @@ def run_layout(
                 free_parts,
                 # Also keep tight macOS containers for exact shortfalls.
                 # Do not probe unrelated stubs or data-only containers that
-                # upstream did not consider resizable.
+                # upstream did not consider resizable. A stub carries the
+                # version of the macOS it was made from, so test stub too.
                 [
                     part for part in installer.parts
                     if part in resizable_parts or (
                         part.type == "Apple_APFS"
                         and part.container is not None
                         and part.os
-                        and any(os.version for os in part.os)
+                        and any(os.version and not os.stub for os in part.os)
                     )
                 ] if is_gpt else [],
                 stub_size,

diff --git a/Engine/overlay/tests/test_omarchy_runtime.py b/Engine/overlay/tests/test_omarchy_runtime.py
@@ -366,11 +366,12 @@ def test_inspect_keeps_tight_containers_filtered_out_by_upstream(self):
             "OMARCHY_ENGINE_JOURNAL": str(self.journal_path),
         })
         runtime.journal.inspection("apple,j314s", "supported")
-        macos = [SimpleNamespace(version="15.7")]
+        macos = [SimpleNamespace(version="15.7", stub=False)]
         tight = SimpleNamespace(type="Apple_APFS", container={"CapacityFree": 1}, os=macos)
         roomy = SimpleNamespace(type="Apple_APFS", container={}, os=macos)
         data = SimpleNamespace(name="data", type="Apple_APFS", container={}, os=[])
-        stub = SimpleNamespace(type="Apple_APFS", container={}, os=[SimpleNamespace(version=None)])
+        # Like upstream's OSInfo, a real stub reports its macOS version.
+        stub = SimpleNamespace(type="Apple_APFS", container={}, os=[SimpleNamespace(version="15.7", stub=True)])
         upstream_data = SimpleNamespace(name="upstream-data", type="Apple_APFS", container={}, os=[])
         recovery = SimpleNamespace(type="Apple_APFS_Recovery", container={}, os=macos)
         unknown = SimpleNamespace(type="Apple_APFS", container=None, os=macos)

diff --git a/Engine/rebuild-python-overlay.py b/Engine/rebuild-python-overlay.py
@@ -15,7 +15,7 @@
 
 BASE_SHA256 = '9e9277384b6c9e8b269cc79b1b24df7bfcdcbb898a596a677b74d1d18050aebe'
 BASE_COMMIT = 'f0469cea0899f3efed8efead604174c7a53c4451'
-VERSION = 'v0.9.2-omarchy.20'
+VERSION = 'v0.9.2-omarchy.27'
 
 _SPEC = importlib.util.spec_from_file_location(
     'verify_source_lock', Path(__file__).resolve().parent / 'verify-source-lock.py')

diff --git a/Engine/source-lock.json b/Engine/source-lock.json
@@ -141,7 +141,7 @@
     }
   },
   "downstream_overlay": {
-    "version": "v0.9.2-omarchy.20",
+    "version": "v0.9.2-omarchy.27",
     "capability": "candidate_bound_full_os_stage_one_authenticated_recovery",
     "engine_modes": [
       "inspect",
@@ -196,7 +196,7 @@
       {
         "path": "overlay/src/omarchy_runtime.py",
         "destination": "src/omarchy_runtime.py",
-        "sha256": "bda8b7baa37052770da32a23b058da143b8b646aed1701866b3ee0338ff6729e"
+        "sha256": "8d5296fe17fe1bac6340a8c2433d0968f9d7f32f262e8a927dd507ec1efb823d"
       },
       {
         "path": "overlay/src/omarchy_stage1.py",
@@ -236,7 +236,7 @@
       {
         "path": "overlay/tests/test_omarchy_runtime.py",
         "destination": "tests/test_omarchy_runtime.py",
-        "sha256": "d46c27fa44a74afcffdcbfa2ab64bc6ae470b8138760df181f28c013932d3cdc"
+        "sha256": "02f4a46d6159f7e189b6e2349dfe43184a6e99256a51a066dd95d02f0500ee57"
       },
       {
         "path": "overlay/tests/test_omarchy_stage1.py",
@@ -270,13 +270,13 @@
     },
     {
       "path": "rebuild-python-overlay.py",
-      "sha256": "f14f10690a2ae558ed8775e2c2ddb8e3ddc2f78f1d340f4899a18ecb47c3414a"
+      "sha256": "e4a6c4f9a3b5e9410d2511c16bf85899e9630713791acf8c59c669bce15e02d0"
     }
   ],
   "validation_artifact": {
-    "filename": "installer-v0.9.2-omarchy.20.tar.gz",
-    "size_bytes": 17839374,
-    "sha256": "7d7d87a934c128e501f8f6287d259195238ed1ae7953336b91738ff63514ea93",
+    "filename": "installer-v0.9.2-omarchy.27.tar.gz",
+    "size_bytes": 17839422,
+    "sha256": "4f9241b0139ba6ccdcfdb3484831002e07e36ba50274279c641ca2020593a15a",
     "reproducibility_scope": "two-identical-python-overlay-repacks-authenticated-base",
     "signature": "absent",
     "metadata_sha256": "2e6181ce6b6e17c11039e04bfadade8d10ae0e11889885ad8c9960b68f179a5d"

diff --git a/Packaging/build-app.sh b/Packaging/build-app.sh
@@ -46,8 +46,8 @@ helper_identifier="$INSTALLER_HELPER_IDENTIFIER"
 app_name="$INSTALLER_APP_NAME.app"
 app_executable_name="OmarchyAppleInstallerApp"
 daemon_plist_name="$helper_identifier.plist"
-engine_file_name="installer-v0.9.2-omarchy.20.tar.gz"
-engine_digest="7d7d87a934c128e501f8f6287d259195238ed1ae7953336b91738ff63514ea93"
+engine_file_name="installer-v0.9.2-omarchy.27.tar.gz"
+engine_digest="4f9241b0139ba6ccdcfdb3484831002e07e36ba50274279c641ca2020593a15a"
 
 if [[ $signing_identity == "-" ]]; then
   client_requirement="identifier \"$app_identifier\""

diff --git a/Sources/OmarchyAppleInstaller/InstallerAllocationRecommendation.swift b/Sources/OmarchyAppleInstaller/InstallerAllocationRecommendation.swift
@@ -59,19 +59,22 @@ public struct InstallerAllocationRecommendation:
         // The engine's hard container floor already protects macOS. A second
         // recommendation threshold can shrink the range as free space grows.
         let usable = available - reservedBytes
+        let margin = min(
+          usable / Self.resizeDriftMarginDivisor,
+          Self.maximumResizeDriftMarginBytes
+        )
+        let marginCeiling = usable - margin
+        // The doubled size becomes the minimum only when it stays below the
+        // margin, so the divider keeps a range and the engine its drift room.
         if let recommended = candidate.recommendedInstallBytes {
           let alignedRecommended = Self.alignUp(recommended, unit: unit)
-          if alignedRecommended <= usable - (usable % unit) {
+          if alignedRecommended < marginCeiling - (marginCeiling % unit) {
             minimum = alignedRecommended
           }
         }
-        let margin = min(
-          usable / Self.resizeDriftMarginDivisor,
-          Self.maximumResizeDriftMarginBytes
-        )
         // The margin is best effort: on a tight disk keep what fits above the
-        // minimum rather than dropping a candidate the reserve still allows.
-        maximum = min(usable, max(usable - margin, minimum))
+        // partition floor rather than dropping a candidate the reserve allows.
+        maximum = min(usable, max(marginCeiling, minimum))
       } else {
         return nil
       }

diff --git a/Sources/OmarchyAppleInstaller/ValidationEngineArtifact.swift b/Sources/OmarchyAppleInstaller/ValidationEngineArtifact.swift
@@ -18,11 +18,11 @@
   /// An installation engine fix ships in a catalog without rebuilding
   /// and re-notarizing the app. Nothing may require them to be equal.
   public struct ValidationEngineArtifactLocator: Sendable {
-    public static let version = "v0.9.2-omarchy.20"
-    public static let fileName = "installer-v0.9.2-omarchy.20.tar.gz"
+    public static let version = "v0.9.2-omarchy.27"
+    public static let fileName = "installer-v0.9.2-omarchy.27.tar.gz"
     public static let expectedDigest =
-      "sha256:7d7d87a934c128e501f8f6287d259195238ed1ae7953336b91738ff63514ea93"
-    public static let expectedSizeBytes: UInt64 = 17_839_374
+      "sha256:4f9241b0139ba6ccdcfdb3484831002e07e36ba50274279c641ca2020593a15a"
+    public static let expectedSizeBytes: UInt64 = 17_839_422
 
     public init() {}
 

diff --git a/Tests/OmarchyAppleInstallerTrustCoreTests/InstallerAllocationRecommendationTests.swift b/Tests/OmarchyAppleInstallerTrustCoreTests/InstallerAllocationRecommendationTests.swift
@@ -30,7 +30,13 @@ final class InstallerAllocationRecommendationTests: XCTestCase {
       let recommendation = try InstallerAllocationRecommendation(
         inventory: inventory, reservedBytes: 10 * gib
       )
-      XCTAssertEqual(recommendation.minimumBytes, (available >= 72 ? 62 : 32) * gib)
+      // 62 GiB is adopted only once it fits under the 5% drift margin.
+      XCTAssertEqual(recommendation.minimumBytes, (available >= 76 ? 62 : 32) * gib)
+      // Near the floor the margin gives way so the install still fits; once
+      // the margin fits above the minimum, the divider can always move.
+      if (available - 10) * 19 > 32 * 20 {
+        XCTAssertGreaterThan(recommendation.maximumBytes, recommendation.minimumBytes)
+      }
       XCTAssertGreaterThanOrEqual(recommendation.maximumBytes, previousMaximum)
       XCTAssertLessThanOrEqual(recommendation.maximumBytes, (available - 10) * gib)
       previousMaximum = recommendation.maximumBytes
@@ -41,6 +47,26 @@ final class InstallerAllocationRecommendationTests: XCTestCase {
     }
   }
 
+  func testRecommendedMinimumKeepsTheDriftMarginAndARange() throws {
+    // Each step of free space from just below to well above where the doubled
+    // size fits: the divider must move and the margin must survive whenever
+    // the doubled size is the minimum.
+    for quarters: UInt64 in 280...320 {
+      let available = quarters * gib / 4
+      let resize = candidate(
+        kind: "resize", source: "disk0s2", length: 200 * gib,
+        minimumInstall: 32 * gib, minimumContainer: 200 * gib - available,
+        recommendedInstall: 62 * gib)
+      let recommendation = try InstallerAllocationRecommendation(
+        inventory: inventory([resize]), reservedBytes: 10 * gib)
+      let usable = available - 10 * gib
+      XCTAssertGreaterThan(recommendation.maximumBytes, recommendation.minimumBytes)
+      if recommendation.minimumBytes == 62 * gib {
+        XCTAssertLessThanOrEqual(recommendation.maximumBytes, usable - usable / 20)
+      }
+    }
+  }
+
   func testLegacyRecommendationDoesNotShrinkCeilingOrFreezeAtFloor() throws {
     var previousMaximum: UInt64 = 0
     for available: UInt64 in 31...100 {
@@ -681,7 +707,8 @@ final class InstallerAllocationRecommendationTests: XCTestCase {
     length: UInt64,
     minimumInstall: UInt64,
     minimumContainer: UInt64 = 0,
-    identityDigest: String? = nil
+    identityDigest: String? = nil,
+    recommendedInstall: UInt64? = nil
   ) -> ValidatedEngineCandidate {
     ValidatedEngineCandidate(
       kind: kind,
@@ -690,7 +717,8 @@ final class InstallerAllocationRecommendationTests: XCTestCase {
       lengthBytes: length,
       minimumInstallBytes: minimumInstall,
       minimumContainerBytes: minimumContainer,
-      identityDigest: identityDigest
+      identityDigest: identityDigest,
+      recommendedInstallBytes: recommendedInstall
     )
   }
 }
diff --git a/Tests/OmarchyAppleInstallerTrustCoreTests/ValidationEngineArtifactTests.swift b/Tests/OmarchyAppleInstallerTrustCoreTests/ValidationEngineArtifactTests.swift
@@ -8,19 +8,19 @@
     func testM3CapableInspectionIdentityIsPinnedExactly() {
       XCTAssertEqual(
         ValidationEngineArtifactLocator.version,
-        "v0.9.2-omarchy.20"
+        "v0.9.2-omarchy.27"
       )
       XCTAssertEqual(
         ValidationEngineArtifactLocator.fileName,
-        "installer-v0.9.2-omarchy.20.tar.gz"
+        "installer-v0.9.2-omarchy.27.tar.gz"
       )
       XCTAssertEqual(
         ValidationEngineArtifactLocator.expectedDigest,
-        "sha256:7d7d87a934c128e501f8f6287d259195238ed1ae7953336b91738ff63514ea93"
+        "sha256:4f9241b0139ba6ccdcfdb3484831002e07e36ba50274279c641ca2020593a15a"
       )
       XCTAssertEqual(
         ValidationEngineArtifactLocator.expectedSizeBytes,
-        17_839_374
+        17_839_422
       )
     }
 

diff --git a/docs/extraction.md b/docs/extraction.md
@@ -73,4 +73,10 @@ The pinned archive is `installer-v0.9.2-omarchy.20.tar.gz`, 17,839,374 bytes, SH
 
 After merging current `main` on 2026-10-03, two repacks with `/usr/bin/python3` 3.9.6 again reproduced that exact pinned digest and size. A repack with Python 3.14.7 produced SHA-256 `e901371a4ba34d901a980b6f7586fc07d14234f9b50724ac4972e43ef35416af`, 17,839,417 bytes. All eight shipped downstream Python modules match the final repository sources byte for byte in both encodings, including the planner's disk-shortfall change. Reproduction must use the recorded interpreter before treating a different archive digest as stale source. The portable source-lock tests now check every downstream input and build recipe against its recorded digest, catching source changes without matching lock updates even when the upstream checkout is unavailable.
 
-Ship installer **2.1.0 or later** together with the new engine and a signed catalog whose `installer.minimumVersion` is at least **2.1.0**. Both release-input templates carry this gate, and the catalog generator refuses a lower minimum for `.18` or newer engines in this lineage. Older installers then show the update-required message before decoding recommendation fields. The bundled inspection pins now select `.20`; signed production catalogs and frozen private-test catalogs are not changed by this source update. Artifact publication, catalog signing and physical installation qualification remain separate release steps.
+## Stub probe and divider margin fixes
+
+Engine `.27` stops probing stub containers. A stub carries the version of the macOS it was made from, so a versioned OS alone admitted it to the limits probes, and one failed probe of a stub on a Mac with an existing Asahi or Omarchy install failed the whole inventory. The filter now admits only versioned OSes that are not stubs. The pinned archive is `installer-v0.9.2-omarchy.27.tar.gz`, 17,839,422 bytes, SHA-256 `4f9241b0139ba6ccdcfdb3484831002e07e36ba50274279c641ca2020593a15a`. Two repacks with macOS `/usr/bin/python3` 3.9.6 produced identical bytes from the authenticated `.14` base and locked v0.9.2 checkout; compared with `.20`, only `omarchy_runtime.py` and `version.tag` changed. The bundled inspection pins and both release-input templates select `.27`.
+
+Swift now withholds the resize drift margin before adopting the recommended (doubled) Omarchy size as the minimum. Adopting it first left a band of free-space states where the minimum equalled the maximum: the divider could not move and no margin remained for the engine's admission check.
+
+Ship installer **2.1.0 or later** together with the new engine and a signed catalog whose `installer.minimumVersion` is at least **2.1.0**. Both release-input templates carry this gate, and the catalog generator refuses a lower minimum for `.18` or newer engines in this lineage. Older installers then show the update-required message before decoding recommendation fields. The bundled inspection pins now select `.27`; signed production catalogs and frozen private-test catalogs are not changed by this source update. Artifact publication, catalog signing and physical installation qualification remain separate release steps.
diff --git a/scripts/release-inputs-aurora.template.json b/scripts/release-inputs-aurora.template.json
@@ -1,8 +1,8 @@
 {
   "payload_name": "omarchy-2026.09.13-aarch64-apple-silicon-aurora-os-package.zip",
-  "engine_name": "installer-v0.9.2-omarchy.20.tar.gz",
+  "engine_name": "installer-v0.9.2-omarchy.27.tar.gz",
   "metadata_name": "installer_data.json",
-  "engine_version": "v0.9.2-omarchy.20",
+  "engine_version": "v0.9.2-omarchy.27",
   "evidence_revision": "4.0.3-mac.2.20260913-aurora",
   "asahi_installer_tag": "v0.9.2",
   "asahi_installer_revision": "dffbb38ef0c00c0431c609ecd8a00f42deb5b24c",
@@ -47,6 +47,6 @@
   "installer": {
     "minimum_version": "2.1.0",
     "latest_version": "2.1.0",
-    "download_url": "https://downloads.aicodelabs.com.au/omarchy-mac/installer/2.1.0/Omarchy-MX-Mac-Installer-2.1.0.pkg"
+    "download_url": "https://downloads.aicodelabs.com.au/omarchy-mac/installer/2.1.0/Omarchy-MX-Mac-Installer-2.1.0.zip"
   }
 }
diff --git a/scripts/release-inputs.template.json b/scripts/release-inputs.template.json
@@ -1,8 +1,8 @@
 {
   "payload_name": "omarchy-2026.09.13-aarch64-apple-silicon-asahi-os-package.zip",
-  "engine_name": "installer-v0.9.2-omarchy.20.tar.gz",
+  "engine_name": "installer-v0.9.2-omarchy.27.tar.gz",
   "metadata_name": "installer_data.json",
-  "engine_version": "v0.9.2-omarchy.20",
+  "engine_version": "v0.9.2-omarchy.27",
   "evidence_revision": "4.0.3-mac.1.20260913",
   "asahi_installer_tag": "v0.9.2",
   "asahi_installer_revision": "dffbb38ef0c00c0431c609ecd8a00f42deb5b24c",
@@ -47,6 +47,6 @@
   "installer": {
     "minimum_version": "2.1.0",
     "latest_version": "2.1.0",
-    "download_url": "https://downloads.aicodelabs.com.au/omarchy-mac/installer/2.1.0/Omarchy-MX-Mac-Installer-2.1.0.pkg"
+    "download_url": "https://downloads.aicodelabs.com.au/omarchy-mac/installer/2.1.0/Omarchy-MX-Mac-Installer-2.1.0.zip"
   }
 }
diff --git a/test/shell.d/apple-installer-identity-test.sh b/test/shell.d/apple-installer-identity-test.sh
@@ -77,7 +77,7 @@ import json, sys
 template, base, stem = sys.argv[1:4]
 installer = json.load(open(template))["installer"]
 version = installer["latest_version"]
-expected = f"{base}/installer/{version}/{stem}-{version}.pkg"
+expected = f"{base}/installer/{version}/{stem}-{version}.zip"
 if installer["download_url"] != expected:
     sys.exit(f"{template}: download_url {installer['download_url']} is not {expected}")
 PY