franklinwh-agate-client/docs/RE_DART_FINDINGS.md

FranklinWH aGate — Dart AOT Reverse-Engineering Findings

Target: split_config.arm64_v8a.apk → lib/arm64-v8a/libapp.so (arm64 Dart AOT snapshot), plus Android glue in base.apk.

Tooling (installed & working)

• blutter (Dart AOT runtime reconstruction) at /tmp/opencode/blutter.
  • Host is aarch64 (matches the binary arch).
  • Dart snapshot version detected automatically: 3.11.5.
  • Build deps installed via apt: python3-pyelftools python3-requests cmake ninja-build build-essential pkg-config libicu-dev libcapstone-dev.
• Output: /tmp/opencode/blutter_out/
  • asm/<package>/<file>.dart — per-file Dart "assembly" with symbols, field offsets, called-function names and inline string literals (this is the readable form).
  • pp.txt — object pool incl. enum instances with their names + raw values.
  • objs.txt, ida_script/, blutter_frida.js.
• jadx 1.5.6 (Java/Kotlin decompiler) for the base.apk DEX glue.
  • Java 21 (OpenJDK 21.0.12.1, /usr/bin/java); CLI at /usr/local/bin/jadx, full install under /home/node/jadx-1.5.6 (bin/jadx, bin/jadx-gui, lib/jadx-1.5.6-all.jar).
  • Full decompile of base.apk at /tmp/opencode/jadx-out/base/ (sources/ — 18,617 .java files — and resources/ incl. the decoded AndroidManifest.xml). Reproduce: jadx -d /tmp/opencode/jadx-out/base /workspaces/typescript-node/base.apk
  • REA MCP's DEX tools (search_android_classes, inspect_android_class, …) need REA_JADX_MCP_JAR → a jadx-headless-mcp 0.7.1 JAR. That JAR is not shipped in the jadx 1.5.6 distribution and is not configured yet — not a blocker, grepping the decompiled sources/ has covered everything so far.

Reproduce:

python3 /tmp/opencode/blutter/blutter.py /tmp/opencode/apk/lib/arm64-v8a /tmp/opencode/blutter_out

Note: blutter yields annotated disassembly + recovered objects, not high-level source. String literals, class/field names, enum values, and call graphs are reliable; arithmetic is read from the disassembly.

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1. Package layout (relevant)

communication_center/
  core/communication_object.dart      # wire envelope
  core/communication_cmd.dart         # command enum + paramKey
  core/communication_mode.dart        # transport enum
  core/encryption.dart                # secret key + payload transform
  core/base_communication.dart
  mqtt/mqtt_manager.dart              # cloud (AWS IoT) transport
  mqtt/mqtt_topic_type.dart           # cmd -> topic mapping
  socket/client_socket.dart, socket_manager.dart   # local TCP transport
  bluetooth/bluetooth_manager.dart, bluetooth_frame.dart, bluetooth_write_queue.dart
  utils/crc16.dart, crc32.dart, utils.dart
franklinwh2/services/communication_service/communication_service.dart   # RPC layer
franklinwh2/services/remote_service/remote_interface.dart               # HTTP RPC layer
franklinwh2/services/eaton_service/eaton_ble_transport.dart             # ESP-svc BLE transport
franklinwh2/utils/device_wifi_utils.dart                                # hotspot join + creds
esp_provisioning_ble/src/...                                            # ESP protocomm

2. Transport selector — CommunicationMode

name	raw
mqtt	0
socket	1
bluetooth	2
http	3
local	4

CommunicationCenter exposes connectOrganized, sendObjectOrganized, completeFutureConnect/Request, timeoutFutureConnect/Request, disposeFutureConnect/Request, matchedRequest. It contains sentinels "do not support http communication" and "do not support local communication" (those modes are handled elsewhere).

3. Wire envelope — CommunicationObject

JSON keys, in the exact insertion/inverse order used by toJson:

cmdType, equipNo, type, timeStamp, snno, len, crc, dataArea, data

Fields present: _Mint field_8, _OneByteString field_10, _Mint field_14 (+ _Mint/_OneByteString further). data is a setter; string const "00000000" is a default (likely crc/dataArea placeholder). cmdType = CommunicationCmd raw, type = CommunicationOperate raw, equipNo = device SN.

• CommunicationOperate: query=0, set=1, command=2, modify=5.
• Crc32::calculate is used in fromJsonString (integrity check of the payload).
• toJsonString() produces the string that is then transformed (see §5).

4. CommunicationCmd (raw → name)

0x00 queryDeviceInfo      0x13 pairPower            0x26 smartLoad2
0x01 networkInfo          0x14 processPairPower     0x27 rebootDevice
0x02 resourceAddress      0x15 checkBluetoothPassword 0x28 debugMode
0x03 sunspecModbus        0x16 goOffGridStatus      0x29 powerOn
0x04 networkSwitch        0x17 aPowerLedSwitch      0x2a chargeDevice
0x05 feedingGridPower     0x18 deviceDetailInfo     0x2b clearFault
0x06 mode                 0x19 deviceApowerInfo     0x2d deviceAddressInfo
0x07 modeV2               0x1a deviceAlarms         0x2e overloadCutOff
0x08 modeSettingV2        0x1c pe                   0x2f wifiFrequecy
0x0a solarInfo            0x1d bms                  0x30 breakerCommissionNotify
0x0b energyManageInfo     0x1e ems                  0x32 breakerComState
0x0c generatorInfo        0x1f mppt                 0x33 breakerLoadStatus
0x0d bluetoothHeartbeat   0x20 aHub                 0x34 breakerIdentifyMe
0x0e scanWifiList         0x21 ctTestReverse
0x0f connectWifi          0x22 deviceData
0x10 connectionStatus     0x23 loadStatus
0x11 networkChannelStatus 0x24 loadStatus2
0x12 networkChannel       0x25 smartLoad

(missing: 0x09, 0x1b, 0x2c, 0x31 — not surfaced as instances.)

5. Encryption — communication_center/core/encryption.dart

generateSecretKey(String equipNo) = hex of (sum(utf8(equipNo)) & 0xFF) (via reduce(sum) → &0xFF → _toPow2String(16)), i.e. a 1-byte key rendered as hex.

encryptObject(obj, key):

1. s = obj.toJsonString(); split on ",".
2. a = UTF-8 of part[0] + "," + part[1] (i.e. {"cmdType":.. and "equipNo":..).
3. b = UTF-8 of join(",", parts[2..]) (the rest).
4. keyInt = int.tryParse(key, radix: …).
5. out[i] = (b[i] + i + len(a) + keyInt) & 0xFF for all i, then append a unchanged.

So on the wire the encrypted body is transform(b) || a (header/keys appended at the end). decryptData is the inverse.

This is a bespoke additive/KSA stream; the exact radix of the key parse and the trailing a handling should be confirmed against a captured frame before trusting it byte-for-byte.

6. Checksums & byte order

• CRC16 (utils/crc16.dart): init 0xFFFF, poly 0xA001 (reflected), i.e. CRC-16/MODBUS; then hi/lo bytes swapped; returned as a 4-hex-digit string (_toPow2String(16)).
• CRC32 (utils/crc32.dart) used for the JSON envelope integrity.
• utils.int16ToBytes / bytesToInt16 = little-endian 16-bit.

7. MQTT transport (cloud) — communication_center/mqtt + Java bridge

Dart side: manager singleton MqttManager._defaultManager; endpoint constant https://a6f63crce3ufk-ats.iot.us-east-2.amazonaws.com (AWS IoT custom domain).

Java side (com.p000franklinwh.mqtt_plugin.MqttPlugin, verified from the jadx decompile):

• Method channel com.franklinwh/plugins/mqtt_plugin/method_channel, events on …/event_channel (name from MqttStatus).
• Method surface: setup / connect / disconnect / subscribe / unsubscribe / publish (the earlier init / setEndpoint / … guess was wrong).
• setup(regionType, identityPoolId, endPointUrl):
  • regionType: 2 → us-east-2, 3 → us-west-1, 4 → us-west-2 (any other value is rejected before setup).
  • Client = AWSIotMqttManager (AWS IoT Android SDK, not raw Paho) with clientID = random UUID per setup, keepAlive = 10 s.
  • Credentials: CognitoCachingCredentialsProvider (unauthenticated Cognito identity pool 5deecc22-4e7f-43b3-8f1d-e54137220126) → AWS IoT credentials provider; MQTT over TLS with temporary credentials issued by AWS IoT — no app-side client certs.
  • Last-will: topic my/lwt/topic, payload "Android client lost connection", QoS 0.
• connect takes no arguments → mqttManager.connect(credentialsProvider, statusCallback).
• subscribe(topic) → subscribeToTopic(topic, QoS 0); publish(topic, message) → publishString(topic, message, QoS 0). Both string payloads.
• Event-channel events:
  • subscribe {topic, message} — message = received bytes decoded as UTF-8;
  • connectionStatuesChange {status: <rawValue>} — sic, "Statues" is the literal event name; status = raw value of the MqttStatus mapping of the SDK status.

Topics — MqttTopicType (name=raw → prefix)

undefined=0  ""              rtC2S=3   "fwh/c2s/rt/"      mngS2C=6   "fwh/s2c/mng/"
authC2S=1    "fwh/c2s/auth/"  rtS2C=4   "fwh/s2c/rt/"      deviceC2S=… "fwh/c2s/device/"
authS2C=2    "fwh/s2c/auth/"  mngC2S=5   "fwh/c2s/mng/"     deviceS2C  "fwh/s2c/device/"
                                                             debugC2S/S2C "fwh/…/{c2s,s2c}/debug/"

MqttTopicType.fromCmd(cmd) selects the topic family for a CommunicationCmd.

8. Socket transport (local TCP) — communication_center/socket

• SocketManager._defaultManager, ClientSocket (getters connected/closed), status enum SocketStatus: closed / connected / connecting.
• CommunicationService._connectBeforeRequest calls CommunicationCenter.connectOrganized(host:, port:) with:
  • host = stored host, else "10.100.1.1" (device hotspot gateway);
  • port constant 0x4650 = 18000 (candidate local port),
  • a Duration and retry loop (up to ~2 retries) are involved.
• BytesToInt16/Int16ToBytes LE framing; Socket Manager send object / receive object.

9. Bluetooth (BLE) transport — communication_center/bluetooth

• BluetoothManager (singleton), BluetoothStatus: closed / connected / connecting / interrupted.
• Frame magics (2 bytes): 0x4A 0xA4 = ACK frame; 0x5A 0xA5 = data frame (triggers _sendAck).
• bluetooth_frame.dart:
  • createBluetoothFrame(content, ?, value): builds content ++ [00 00 00 00] ++ int16LE(totalLen) ++ int16LE(value) ++ sn, computes Crc16::calculate over that, hex→2 bytes, writes them into the 00 00 00 00 placeholder (indices 2..3). totalLen = len(content)+6+len(sn).
  • helpers: magicEquals, magicInData, snInData, contentInData, mtuToData (MTU chunking).
  • Exact field order still to be confirmed against a live btsnoop capture.
• Heartbeat = Dart timer (startBluetoothHeartbeat, cancelBluetoothHeartbeat, _bluetoothHeartbeat, [Bluetooth] Heartbeat Timeout), command bluetoothHeartbeat (0x0d).

ESP provisioning (WiFi onboarding over BLE) — esp_provisioning_ble

• /terminal-style endpoints (ESP protocomm): prov-session, prov-scan, prov-config, custom-data.
• EspProv handles EstablishSessionStatus; security.dart (sec0) & security1.dart (sec1): ECDH (Curve25519) → shared key, verification, abcd1234 present as a PoP, AES-CTR (crypt.dart: key/iv/crypt).
• Service UUID 021a9004-0382-4aea-bff4-6b3f1c5adfb4 is used by franklinwh2/services/eaton_service/eaton_ble_transport.dart (Eaton/EatonBreaker path). The provisioning GATT characteristics are referenced indirectly; confirm via a device scan.

10. Local hot-spot credential derivation — franklinwh2/utils/device_wifi_utils.dart

DeviceWifiUtils (static):

• getDeviceApSsid(sn):
  • if sn.length == 20 → "AP_" + sn.substring(11); else log "deviceSn is invalid" → "AP_" + sn.
• getDeviceApDefaultPwd(sn):
  • if sn.length == 20 → sn.substring(8); else → "12345678".
• connectDeviceWifiWithSSID(ssid, pwd) → wifi_iot connect; disconnectDeviceWifi → disconnect; forceWifiUsage toggles the process binding; caches last ssid/pwd in statics.

The length check is field_7 == 0x28 on a Smi length ⇒ length == 20. Derived values are the offline fallback; the authoritative values come from /terminal/getHotSpotInfo and /terminal/getHosSpotPassword.

11. HTTP layer — local vs cloud

Every operation has a local (/terminal/…) and cloud (/manage/…) route, selected by mode. Local base is https://IP:PORT (string literal), device IP in deviceIp, plus four X-Device-* headers (-IP, -Referer, -Requested-With, -Accept-Language) located in the base.apk DEX string pool — class binding in progress, see §13.

Local device endpoints (subset, /terminal/):

/terminal/getHotSpotInfo        /terminal/getHotSpotInfo/v2   /terminal/getHosSpotPassword
/terminal/obtainAgateInfo       /terminal/updateHotSpotInfo
/terminal/sendMqtt              /terminal/getDeviceInfoV2      /terminal/getDeviceCompositeInfo
/terminal/queryGeneratorData    /terminal/selectDeviceOverallInfo
/terminal/getGatewaySystemSetting   /terminal/system/getSystemSetting
/terminal/initialize/installerOktaLogin   /terminal/initialize/mfa/*
/terminal/mfa/*   /terminal/getPersonalInfo   /terminal/updatePersonalInfo

Cloud: https://e-api.franklinwh.com/api/appapi; https://energy.franklinwh.com/{hes-gateway, hes-tariff-collection, api-energy/*, api-smart/*, api-user/mfa/*, api-vpp-portal}; https://api.franklin-wh.com:10443/api/appapi; https://sunrun.okta.com/oauth2/default.

RemoteInterface returns Stream<HttpResultEntity<…>> per endpoint. CommunicationService exposes typed RPCs: queryDeviceInfo, queryAPowerData, queryCircuitsInfo, queryModes1/2, querySmartLoadInfo, queryNewSmartLoadInfo, queryCTTestReverse, queryAHubDetailInfo, queryEmsInfoBySocket, queryLoadStatusInfo, queryNewLoadStatusInfo, queryOverloadCutOff, queryDebugModeInfo, queryChargePower, queryGoOffGridStatus, plus _request(cmd, sn, operate, {arguments, mode}) as the core dispatch.

12. Eaton breaker / UDP keys

eaton_service/eaton_udp_keys.dart + eaton_breaker_service.dart deal with primary/secondary Unicast/Multicast UDP keys (etn_udp_keys_…), versioned (VER1), keyed storage, status strings (Success, Failure to store UDP Keys, UDP Key Format error).

13. Java glue (base.apk) — JADX decompile

/tmp/opencode/jadx-out/base/sources (18,617 files; see Tooling). The Java layer is platform plumbing only — no device-protocol logic; the protocol lives entirely in the Dart AOT layer. (The MQTT bridge is covered in §7.)

com.franklinwh.franklinwh2.method_channel.MethodHandlerManager

Singleton holding a LinkedHashMap<String, BaseMethodHandler>; the constructor calls registerHandlers(), which registers exactly five handlers on the com.FranklinWH.FamilyEnergy/method_channel channel: OpenSystemWifiSetting, NetworkInfoCompat, BuildConfig, MigrateData, ShareInfoToOtherApp (all under method_channel/method_handlers/). All UI/system helpers — opening the system Wi-Fi settings, network state, build config, DB migration, Android share sheet. No device-communication surface.

com.alternadom.wifiiot.WifiIotPlugin (the wifi_iot plugin)

Thin wrapper over Android WifiManager — this is how the app joins the device SoftAP. Full method surface (26, from the Kotlin string dispatch):

connect, findAndConnect, disconnect, isConnected, setEnabled,
getIP, getSSID, getBSSID, getFrequency, getCurrentSignalStrength,
loadWifiList, registerWifiNetwork, removeWifiNetwork, isRegisteredWifiNetwork,
setSSIDHidden, isSSIDHidden, getClientList,
SoftAP: setWiFiAPEnabled, getWiFiAPState, isWiFiAPEnabled, getWiFiAPSSID,
setWiFiAPSSID, getWiFiAPPreSharedKey, setWiFiAPPreSharedKey,
forceWifiUsage, showWritePermissionSettings

Location-permission request codes: 65655435 (load list), 65655436 (listen), 65655437 (find & connect), 65655438 (isConnected). Nothing protocol-specific.

X-Device-* headers — located in DEX, class binding in progress

X-Device-IP, X-Device-Referer, X-Device-Requested-With, X-Device-Accept-Language exist as adjacent entries in the classes5.dex string pool (i.e. one constant map of 4 headers) but do not appear as literals in any decompiled class (the only jadx decompile errors were in unrelated com.google.android.material.shadow.*). They are absent from the Dart libapp.so string pool too. So a Kotlin class in classes5.dex sets them at runtime — consistent with cloud HTTP requests carrying a device-IP header (cloud → device proxying). Identifying the referencing class via a direct DEX string-reference scan is in progress (workaround while REA's DEX tools stay unavailable without REA_JADX_MCP_JAR).

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Open items

Resolved by the JADX decompile of base.apk (see §7, §13): MqttPlugin internals (actual method names setup/connect/…, AWSIotMqttManager + Cognito credentials, keepAlive 10 s, LWT, QoS 0, event names), MethodHandlerManager handler list, WifiIotPlugin method surface.

Still open:

1. Exact BLE frame field order & the 2-byte magic semantics (confirm with btsnoop).
2. Exact encryptObject radix + trailing-header handling.
3. Local HTTP port + TLS behavior for https://IP:PORT (device self-signed cert?).
4. Local socket port confirmation (18000 candidate) and whether local RPC uses socket vs /terminal HTTP vs local MQTT.
5. Which class in classes5.dex sets the X-Device-* headers and their exact values (string-pool location confirmed; class binding in progress — §13).
6. (Tooling, optional) Enable REA's DEX tools: obtain a jadx-headless-mcp 0.7.1 JAR and set REA_JADX_MCP_JAR.