diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a53ba3f
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+.DS_Store
+build/
+*.xcresult
+xcuserdata/
+*.ipa
diff --git a/HelloWorld.xcodeproj/project.pbxproj b/HelloWorld.xcodeproj/project.pbxproj
new file mode 100644
index 0000000..245becb
--- /dev/null
+++ b/HelloWorld.xcodeproj/project.pbxproj
@@ -0,0 +1,194 @@
+// !$*UTF8*$!
+{
+	archiveVersion = 1;
+	classes = {};
+	objectVersion = 56;
+	objects = {
+
+/* Begin PBXBuildFile section */
+		A10000000000000000000001 /* App.swift in Sources */ = {isa = PBXBuildFile; fileRef = A10000000000000000000002 /* App.swift */; };
+/* End PBXBuildFile section */
+
+/* Begin PBXFileReference section */
+		A10000000000000000000002 /* App.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = App.swift; sourceTree = "<group>"; };
+		A10000000000000000000003 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
+		A10000000000000000000004 /* HelloWorld.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = HelloWorld.app; sourceTree = BUILT_PRODUCTS_DIR; };
+/* End PBXFileReference section */
+
+/* Begin PBXFrameworksBuildPhase section */
+		A10000000000000000000005 /* Frameworks */ = {
+			isa = PBXFrameworksBuildPhase;
+			buildActionMask = 2147483647;
+			files = ();
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+/* End PBXFrameworksBuildPhase section */
+
+/* Begin PBXGroup section */
+		A10000000000000000000006 = {
+			isa = PBXGroup;
+			children = (
+				A10000000000000000000007 /* Sources */,
+				A10000000000000000000008 /* Resources */,
+				A10000000000000000000009 /* Products */,
+			);
+			sourceTree = "<group>";
+		};
+		A10000000000000000000007 /* Sources */ = {
+			isa = PBXGroup;
+			children = (A10000000000000000000002 /* App.swift */,);
+			path = Sources;
+			sourceTree = "<group>";
+		};
+		A10000000000000000000008 /* Resources */ = {
+			isa = PBXGroup;
+			children = (A10000000000000000000003 /* Info.plist */,);
+			path = Resources;
+			sourceTree = "<group>";
+		};
+		A10000000000000000000009 /* Products */ = {
+			isa = PBXGroup;
+			children = (A10000000000000000000004 /* HelloWorld.app */,);
+			name = Products;
+			sourceTree = "<group>";
+		};
+/* End PBXGroup section */
+
+/* Begin PBXNativeTarget section */
+		A1000000000000000000000A /* HelloWorld */ = {
+			isa = PBXNativeTarget;
+			buildConfigurationList = A1000000000000000000000B /* Build configuration list for PBXNativeTarget "HelloWorld" */;
+			buildPhases = (
+				A1000000000000000000000C /* Sources */,
+				A10000000000000000000005 /* Frameworks */,
+				A1000000000000000000000D /* Resources */,
+			);
+			buildRules = ();
+			dependencies = ();
+			name = HelloWorld;
+			productName = HelloWorld;
+			productReference = A10000000000000000000004 /* HelloWorld.app */;
+			productType = "com.apple.product-type.application";
+		};
+/* End PBXNativeTarget section */
+
+/* Begin PBXProject section */
+		A1000000000000000000000E /* Project object */ = {
+			isa = PBXProject;
+			attributes = {
+				BuildIndependentTargetsInParallel = 1;
+				LastSwiftUpdateCheck = 1620;
+				LastUpgradeCheck = 1620;
+				TargetAttributes = {
+					A1000000000000000000000A = {
+						CreatedOnToolsVersion = 16.2;
+						DevelopmentTeam = HY3W4U256Z;
+						ProvisioningStyle = Automatic;
+					};
+				};
+			};
+			buildConfigurationList = A1000000000000000000000F /* Build configuration list for PBXProject "HelloWorld" */;
+			compatibilityVersion = "Xcode 14.0";
+			developmentRegion = en;
+			hasScannedForEncodings = 0;
+			knownRegions = (en, Base,);
+			mainGroup = A10000000000000000000006;
+			productRefGroup = A10000000000000000000009 /* Products */;
+			projectDirPath = "";
+			projectRoot = "";
+			targets = (A1000000000000000000000A /* HelloWorld */,);
+		};
+/* End PBXProject section */
+
+/* Begin PBXResourcesBuildPhase section */
+		A1000000000000000000000D /* Resources */ = {
+			isa = PBXResourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = ();
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+/* End PBXResourcesBuildPhase section */
+
+/* Begin PBXSourcesBuildPhase section */
+		A1000000000000000000000C /* Sources */ = {
+			isa = PBXSourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (A10000000000000000000001 /* App.swift in Sources */,);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+/* End PBXSourcesBuildPhase section */
+
+/* Begin XCBuildConfiguration section */
+		A10000000000000000000010 /* Debug */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ALWAYS_SEARCH_USER_PATHS = NO;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
+				SDKROOT = iphoneos;
+			};
+			name = Debug;
+		};
+		A10000000000000000000011 /* Release */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				ALWAYS_SEARCH_USER_PATHS = NO;
+				IPHONEOS_DEPLOYMENT_TARGET = 15.0;
+				SDKROOT = iphoneos;
+			};
+			name = Release;
+		};
+		A10000000000000000000012 /* Debug */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				CODE_SIGN_STYLE = Automatic;
+				CURRENT_PROJECT_VERSION = 1;
+				DEVELOPMENT_TEAM = HY3W4U256Z;
+				GENERATE_INFOPLIST_FILE = NO;
+				INFOPLIST_FILE = Resources/Info.plist;
+				MARKETING_VERSION = 1.0;
+				PRODUCT_BUNDLE_IDENTIFIER = local.proxmox.helloworld.e2e;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SUPPORTED_PLATFORMS = iphoneos;
+				SWIFT_VERSION = 6.0;
+				TARGETED_DEVICE_FAMILY = 1;
+			};
+			name = Debug;
+		};
+		A10000000000000000000013 /* Release */ = {
+			isa = XCBuildConfiguration;
+			buildSettings = {
+				CODE_SIGN_STYLE = Automatic;
+				CURRENT_PROJECT_VERSION = 1;
+				DEVELOPMENT_TEAM = HY3W4U256Z;
+				GENERATE_INFOPLIST_FILE = NO;
+				INFOPLIST_FILE = Resources/Info.plist;
+				MARKETING_VERSION = 1.0;
+				PRODUCT_BUNDLE_IDENTIFIER = local.proxmox.helloworld.e2e;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				SUPPORTED_PLATFORMS = iphoneos;
+				SWIFT_COMPILATION_MODE = wholemodule;
+				SWIFT_OPTIMIZATION_LEVEL = "-O";
+				SWIFT_VERSION = 6.0;
+				TARGETED_DEVICE_FAMILY = 1;
+			};
+			name = Release;
+		};
+/* End XCBuildConfiguration section */
+
+/* Begin XCConfigurationList section */
+		A1000000000000000000000B /* Build configuration list for PBXNativeTarget "HelloWorld" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (A10000000000000000000012 /* Debug */, A10000000000000000000013 /* Release */,);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
+		A1000000000000000000000F /* Build configuration list for PBXProject "HelloWorld" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (A10000000000000000000010 /* Debug */, A10000000000000000000011 /* Release */,);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
+/* End XCConfigurationList section */
+	};
+	rootObject = A1000000000000000000000E /* Project object */;
+}
diff --git a/README.md b/README.md
index 274bfb9..73ca4ca 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,94 @@
-# helloworld-ios-ota
+# HelloWorld for iOS
 
-Signed iOS OTA builds and installation manifests for HelloWorld
\ No newline at end of file
+A minimal UIKit application plus a command-line build and installation workflow.
+The workflow was tested with:
+
+- Intel macOS Sonoma 14.8.7 running in Proxmox
+- Xcode 16.2 and the iOS 18.2 SDK
+- An iPhone 15 running iOS 26.5.2
+- `pymobiledevice3` 9.36.0
+
+The host Xcode does not need to support the phone's installed iOS version. The
+script builds the Xcode **target** directly for `iphoneos`, which avoids Xcode's
+destination compatibility check, and uses `pymobiledevice3` to install the
+result through Apple's installation service.
+
+## Prerequisites
+
+1. Select Xcode and finish its first-launch setup:
+
+   ```bash
+   sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer
+   sudo xcodebuild -license accept
+   sudo xcodebuild -runFirstLaunch
+   ```
+
+2. Install a current `pymobiledevice3`. Version 2.30.0 is too old for current
+   AltServer JIT support because it does not expose the `mounter` command.
+
+   ```bash
+   brew install openssl@3
+   python3 -m pip install -U pymobiledevice3
+   ```
+
+3. Sign in to the Apple account in Xcode, pair the iPhone, and enable
+   **Settings > Privacy & Security > Developer Mode** on the phone.
+
+4. Ensure the phone is registered with the Personal Team. AltServer can perform
+   the initial registration. A free Personal Team profile expires after seven
+   days, so rerun the script to rebuild and reinstall before expiration.
+
+## Build and install
+
+Connect and unlock one iPhone, then run:
+
+```bash
+./scripts/build-install.sh
+```
+
+To select a device explicitly and launch the app after installation:
+
+```bash
+./scripts/build-install.sh \
+  --udid DEVICE_UDID \
+  --launch
+```
+
+The launch step requires the phone to remain unlocked. The build and signed IPA
+are written under `build/device/`.
+
+Useful overrides:
+
+```bash
+TEAM_ID=HY3W4U256Z \
+BUNDLE_ID=local.proxmox.helloworld.e2e \
+CONFIGURATION=Debug \
+./scripts/build-install.sh
+```
+
+Use `--build-only` to compile, sign, package, and validate without installing.
+When the phone is disconnected, pass its UDID explicitly so the script can
+still verify the provisioning profile:
+
+```bash
+./scripts/build-install.sh --build-only --udid DEVICE_UDID
+```
+
+## Why this works with an older Xcode
+
+An ordinary scheme build aimed at an iOS 26 phone causes Xcode 16.2 to reject
+the destination before compilation. This project instead uses a target-level
+device build:
+
+```bash
+xcodebuild -project HelloWorld.xcodeproj \
+  -target HelloWorld \
+  -sdk iphoneos \
+  -allowProvisioningUpdates \
+  build
+```
+
+The resulting ARM64 app targets iOS 15 or later and therefore runs on iOS 26.
+Installation and device queries are handled independently by
+`pymobiledevice3`, which supports newer device protocols without requiring a
+newer macOS release.
diff --git a/Resources/Info.plist b/Resources/Info.plist
new file mode 100644
index 0000000..5b2bd97
--- /dev/null
+++ b/Resources/Info.plist
@@ -0,0 +1,36 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+    <key>CFBundleDevelopmentRegion</key>
+    <string>en</string>
+    <key>CFBundleDisplayName</key>
+    <string>Hello World</string>
+    <key>CFBundleExecutable</key>
+    <string>HelloWorld</string>
+    <key>CFBundleIdentifier</key>
+    <string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+    <key>CFBundleInfoDictionaryVersion</key>
+    <string>6.0</string>
+    <key>CFBundleName</key>
+    <string>HelloWorld</string>
+    <key>CFBundlePackageType</key>
+    <string>APPL</string>
+    <key>CFBundleShortVersionString</key>
+    <string>1.0</string>
+    <key>CFBundleVersion</key>
+    <string>1</string>
+    <key>LSRequiresIPhoneOS</key>
+    <true/>
+    <key>MinimumOSVersion</key>
+    <string>15.0</string>
+    <key>UILaunchScreen</key>
+    <dict/>
+    <key>UISupportedInterfaceOrientations</key>
+    <array>
+        <string>UIInterfaceOrientationPortrait</string>
+        <string>UIInterfaceOrientationLandscapeLeft</string>
+        <string>UIInterfaceOrientationLandscapeRight</string>
+    </array>
+</dict>
+</plist>
diff --git a/Sources/App.swift b/Sources/App.swift
new file mode 100644
index 0000000..3a60a99
--- /dev/null
+++ b/Sources/App.swift
@@ -0,0 +1,31 @@
+import UIKit
+
+@main
+final class AppDelegate: UIResponder, UIApplicationDelegate {
+    var window: UIWindow?
+
+    func application(
+        _ application: UIApplication,
+        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? = nil
+    ) -> Bool {
+        let label = UILabel()
+        label.text = "Hello, world!"
+        label.font = .systemFont(ofSize: 32, weight: .bold)
+        label.textAlignment = .center
+
+        let viewController = UIViewController()
+        viewController.view.backgroundColor = .systemBackground
+        viewController.view.addSubview(label)
+        label.translatesAutoresizingMaskIntoConstraints = false
+        NSLayoutConstraint.activate([
+            label.centerXAnchor.constraint(equalTo: viewController.view.centerXAnchor),
+            label.centerYAnchor.constraint(equalTo: viewController.view.centerYAnchor),
+        ])
+
+        let window = UIWindow(frame: UIScreen.main.bounds)
+        window.rootViewController = viewController
+        window.makeKeyAndVisible()
+        self.window = window
+        return true
+    }
+}
diff --git a/scripts/build-install.sh b/scripts/build-install.sh
new file mode 100755
index 0000000..eca3a9c
--- /dev/null
+++ b/scripts/build-install.sh
@@ -0,0 +1,192 @@
+#!/bin/bash
+
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+PROJECT_PATH="$ROOT_DIR/HelloWorld.xcodeproj"
+TARGET_NAME="HelloWorld"
+TEAM_ID="${TEAM_ID:-HY3W4U256Z}"
+BUNDLE_ID="${BUNDLE_ID:-local.proxmox.helloworld.e2e}"
+CONFIGURATION="${CONFIGURATION:-Debug}"
+DEVICE_UDID="${DEVICE_UDID:-}"
+BUILD_ROOT="$ROOT_DIR/build/device"
+BUILD_ONLY=0
+LAUNCH=0
+
+usage() {
+    echo "Usage: $0 [--udid UDID] [--bundle-id ID] [--team-id ID] [--configuration NAME] [--build-only] [--launch]"
+}
+
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        --udid)
+            DEVICE_UDID="${2:?--udid requires a value}"
+            shift 2
+            ;;
+        --bundle-id)
+            BUNDLE_ID="${2:?--bundle-id requires a value}"
+            shift 2
+            ;;
+        --team-id)
+            TEAM_ID="${2:?--team-id requires a value}"
+            shift 2
+            ;;
+        --configuration)
+            CONFIGURATION="${2:?--configuration requires a value}"
+            shift 2
+            ;;
+        --build-only)
+            BUILD_ONLY=1
+            shift
+            ;;
+        --launch)
+            LAUNCH=1
+            shift
+            ;;
+        -h|--help)
+            usage
+            exit 0
+            ;;
+        *)
+            echo "Unknown argument: $1" >&2
+            usage >&2
+            exit 2
+            ;;
+    esac
+done
+
+for command_name in xcodebuild security codesign python3; do
+    if ! command -v "$command_name" >/dev/null 2>&1; then
+        echo "Required command not found: $command_name" >&2
+        exit 1
+    fi
+done
+
+if command -v pymobiledevice3 >/dev/null 2>&1; then
+    PMD=(pymobiledevice3)
+elif python3 -c 'import pymobiledevice3' >/dev/null 2>&1; then
+    PMD=(python3 -m pymobiledevice3)
+else
+    echo "pymobiledevice3 is required. Install it with: python3 -m pip install -U pymobiledevice3" >&2
+    exit 1
+fi
+
+run_pmd() {
+    PYTHONWARNINGS=ignore "${PMD[@]}" --no-color "$@"
+}
+
+if [[ -z "$DEVICE_UDID" ]]; then
+    device_json="$(run_pmd usbmux list)"
+    DEVICE_UDID="$(printf '%s' "$device_json" | python3 -c '
+import json, sys
+devices = json.load(sys.stdin)
+print(devices[0].get("Identifier", "") if len(devices) == 1 else "")
+')"
+    if [[ -z "$DEVICE_UDID" ]]; then
+        echo "Connect exactly one unlocked iPhone, or pass --udid explicitly." >&2
+        exit 1
+    fi
+fi
+
+echo "Building $BUNDLE_ID for device $DEVICE_UDID"
+
+xcodebuild \
+    -project "$PROJECT_PATH" \
+    -target "$TARGET_NAME" \
+    -configuration "$CONFIGURATION" \
+    -sdk iphoneos \
+    -allowProvisioningUpdates \
+    -allowProvisioningDeviceRegistration \
+    PRODUCT_BUNDLE_IDENTIFIER="$BUNDLE_ID" \
+    DEVELOPMENT_TEAM="$TEAM_ID" \
+    SYMROOT="$BUILD_ROOT" \
+    OBJROOT="$BUILD_ROOT/Intermediates" \
+    build
+
+APP_PATH="$BUILD_ROOT/$CONFIGURATION-iphoneos/$TARGET_NAME.app"
+IPA_PATH="$BUILD_ROOT/$TARGET_NAME.ipa"
+
+if [[ ! -d "$APP_PATH" ]]; then
+    echo "Expected app was not produced: $APP_PATH" >&2
+    exit 1
+fi
+
+actual_bundle_id="$(/usr/libexec/PlistBuddy -c 'Print :CFBundleIdentifier' "$APP_PATH/Info.plist")"
+if [[ "$actual_bundle_id" != "$BUNDLE_ID" ]]; then
+    echo "Bundle ID mismatch: expected $BUNDLE_ID, found $actual_bundle_id" >&2
+    exit 1
+fi
+
+codesign --verify --deep --strict "$APP_PATH"
+
+TEMP_DIR="$(mktemp -d /tmp/helloworld-install.XXXXXX)"
+cleanup() {
+    if [[ -n "${TEMP_DIR:-}" && "$TEMP_DIR" == /tmp/helloworld-install.* ]]; then
+        rm -rf "$TEMP_DIR"
+    fi
+}
+trap cleanup EXIT
+
+PROFILE_PLIST="$TEMP_DIR/profile.plist"
+security cms -D -i "$APP_PATH/embedded.mobileprovision" > "$PROFILE_PLIST"
+
+if ! /usr/libexec/PlistBuddy -c 'Print :ProvisionedDevices' "$PROFILE_PLIST" 2>/dev/null | grep -Fq "$DEVICE_UDID"; then
+    echo "Provisioning profile does not contain device UDID $DEVICE_UDID." >&2
+    echo "Register the phone with the Apple team, then rerun this script." >&2
+    exit 1
+fi
+
+profile_name="$(/usr/libexec/PlistBuddy -c 'Print :Name' "$PROFILE_PLIST")"
+profile_expiration="$(/usr/libexec/PlistBuddy -c 'Print :ExpirationDate' "$PROFILE_PLIST")"
+
+mkdir -p "$TEMP_DIR/Payload"
+ditto "$APP_PATH" "$TEMP_DIR/Payload/$TARGET_NAME.app"
+ditto -c -k --keepParent "$TEMP_DIR/Payload" "$IPA_PATH"
+
+echo "Signature and provisioning profile validated."
+echo "Profile: $profile_name"
+echo "Expires: $profile_expiration"
+echo "IPA: $IPA_PATH"
+
+if [[ "$BUILD_ONLY" -eq 1 ]]; then
+    echo "Build-only verification complete."
+    exit 0
+fi
+
+run_pmd apps install --udid "$DEVICE_UDID" "$APP_PATH"
+
+query_output="$(run_pmd apps query --udid "$DEVICE_UDID" "$BUNDLE_ID")"
+if ! printf '%s' "$query_output" | grep -Fq '"ProfileValidated": true'; then
+    echo "The app installed, but the device did not report a validated profile." >&2
+    exit 1
+fi
+
+echo "Installed and profile-validated: $BUNDLE_ID"
+
+if [[ "$LAUNCH" -eq 1 ]]; then
+    if ! command -v xcrun >/dev/null 2>&1; then
+        echo "xcrun is required for --launch." >&2
+        exit 1
+    fi
+
+    device_list_json="$TEMP_DIR/devicectl.json"
+    xcrun devicectl list devices --json-output "$device_list_json" >/dev/null
+    core_device_id="$(python3 -c '
+import json, sys
+path, udid = sys.argv[1:]
+with open(path, encoding="utf-8") as stream:
+    devices = json.load(stream).get("result", {}).get("devices", [])
+for device in devices:
+    if device.get("hardwareProperties", {}).get("udid") == udid:
+        print(device.get("identifier", ""))
+        break
+' "$device_list_json" "$DEVICE_UDID")"
+
+    if [[ -z "$core_device_id" ]]; then
+        echo "Unable to map UDID to a CoreDevice identifier for launch." >&2
+        exit 1
+    fi
+
+    xcrun devicectl device process launch --device "$core_device_id" "$BUNDLE_ID"
+    echo "Launched $BUNDLE_ID"
+fi