diff --git a/.gitignore b/.gitignore
index 69b4b6b..d03d680 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 #test scripts
 emulate.ts
 test-database.ts
+script.*.ts
 
 # Database files
 *.db
diff --git a/src/index.ts b/src/index.ts
index fe21b09..d581250 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,7 +1,7 @@
 import "dotenv/config";
 import { handleUplinks } from "./logic/mqtt";
 import { Request, Response } from "express";
-import { app, m3ter } from "./logic/context";
+import { app, m3ter, rollup } from "./logic/context";
 import setupDatabase, {
   getAllMeterRecords,
   saveMeter,
@@ -13,8 +13,6 @@ handleUplinks();
 // Initialize database tables and jobs
 setupDatabase();
 
-console.log("[server]: Server is starting...", process.env); // todo: remove
-
 app.get("/", async (req: Request, res: Response) => {
   const m3ters = getAllMeterRecords();
   res.render("index", { m3ters });
@@ -25,10 +23,12 @@ app.post("/", async (req: Request, res: Response) => {
   try {
     const tokenId = (await req.body).tokenId;
     const publicKey = await m3ter.publicKey(tokenId);
+    const latestNonce = await rollup.nonce(tokenId);
     saveMeter({
       publicKey,
       tokenId,
-      latestNonce: 0, // Initialize latestNonce to 0
+      latestNonce: Number(latestNonce),
+      devEui: (await req.body).devEui ?? null,
     });
   } catch (err) {
     console.error(err);
diff --git a/src/logic/context.ts b/src/logic/context.ts
index aa38f6e..407287e 100644
--- a/src/logic/context.ts
+++ b/src/logic/context.ts
@@ -32,8 +32,11 @@ app.listen(port, () => {
 const provider = new JsonRpcProvider(process.env.MAINNET_RPC);
 
 export const m3ter = new Contract(
-  "0x40a36C0eF29A49D1B1c1fA45fab63762f8FC423F",
-  ["function publicKey(uint256) view returns (bytes32)"],
+  "0x7c6FEF064603B91bE9d739fE981c28Fd82a6D62b", // "0x40a36C0eF29A49D1B1c1fA45fab63762f8FC423F",
+  [
+    "function publicKey(uint256) view returns (bytes32)",
+    "function tokenID(bytes32) view returns (uint256)",
+  ],
   provider
 );
 
diff --git a/src/logic/mqtt.ts b/src/logic/mqtt.ts
index a8833bc..139dbab 100644
--- a/src/logic/mqtt.ts
+++ b/src/logic/mqtt.ts
@@ -2,7 +2,16 @@ import { connect } from "mqtt";
 import { enqueue } from "./grpc";
 import { interact } from "./arweave";
 import { encode } from "./encode";
-import { getMeterByPublicKey, insertTransaction, updateMeterNonce } from "../store/sqlite";
+import { m3ter as m3terContract, rollup as rollupContract } from "./context";
+import {
+  getAllMeterRecords,
+  getMeterByDevEui,
+  getMeterByPublicKey,
+  insertTransaction,
+  saveMeter,
+  updateMeterDevEui,
+  updateMeterNonce,
+} from "../store/sqlite";
 import { State, TransactionRecord } from "../types";
 import { getProverURL, sendPendingTransactionsToProver } from "./verify";
 import { decodePayload } from "./decode";
@@ -36,30 +45,63 @@ export function handleUplinks() {
   });
 }
 
-async function handleMessage(blob: Buffer) {
+export async function handleMessage(blob: Buffer) {
   try {
     const message = JSON.parse(blob.toString());
 
     console.log("[info] Received uplink from device:", JSON.stringify(message));
 
-    const payload = Buffer.from(message["data"], "hex");
+    const payload = Buffer.from(message["data"], "base64");
     // encode transaction into standard format (payload is hex string)
     // format: nonce | energy | signature | voltage | device_id | longitude | latitude
     const transactionHex = payload;
     const decoded = decodePayload(transactionHex);
-    const publicKey = decoded.extensions.deviceId;
+    let publicKey = decoded.extensions.deviceId;
 
     console.log("[info] Decoded payload:", decoded);
 
-    if (!publicKey) {
-      throw new Error("Invalid Public Key");
+    if (publicKey) {
+      // save public key with device EUI mapping if not already saved
+      const existingMeter = getMeterByPublicKey(`0x${publicKey}`);
+
+      if (!existingMeter) {
+        const tokenId = Number(await m3terContract.tokenID(`0x${publicKey}`));
+        if (tokenId === 0) {
+          throw new Error("Token ID not found for public key: " + publicKey);
+        }
+
+        const latestNonce = Number(await rollupContract.nonce(tokenId));
+
+        // save new meter with devEui
+        const newMeter = {
+          publicKey: `0x${publicKey}`,
+          devEui: message["deviceInfo"]["devEui"],
+          tokenId,
+          latestNonce,
+        };
+        saveMeter(newMeter);
+        console.log("[info] Saved new meter:", newMeter);
+      } else if (existingMeter && !existingMeter.devEui) {
+        // update existing meter with devEui if not already set
+        updateMeterDevEui(`0x${publicKey}`, message["deviceInfo"]["devEui"]);
+        console.log("[info] Updated meter with DevEui:", existingMeter.tokenId);
+      }
+    } else {
+      // try to find meter by DevEui
+      const devEui = message["deviceInfo"]["devEui"];
+      const meterByDevEui = getMeterByDevEui(devEui);
+
+      if (!meterByDevEui) {
+        throw new Error("Device EUI not associated with any meter: " + devEui);
+      }
+
+      publicKey = meterByDevEui.publicKey.replace("0x", "");
     }
 
-    const m3ter = getMeterByPublicKey(publicKey ?? "");
+    const m3ter = getMeterByPublicKey(`0x${publicKey}`) ?? null;
 
     if (!m3ter) {
-      console.error("Meter not found for public key:", publicKey);
-      return;
+      throw new Error("Meter not found for public key: " + publicKey);
     }
 
     console.log(
@@ -74,10 +116,7 @@ async function handleMessage(blob: Buffer) {
     // if device nonce is correct
     const expectedNonce = m3ter.latestNonce + 1;
 
-    let state;
     if (decoded.nonce === expectedNonce) {
-      state = { is_on: true };
-
       console.log("[info] Nonce is valid:", decoded.nonce);
       // Upload to arweave
       await interact(m3ter.tokenId, decoded);
@@ -118,13 +157,16 @@ async function handleMessage(blob: Buffer) {
       }
     }
 
+    const state =
+      decoded.nonce === m3ter.latestNonce + 1 || decoded.nonce === 0
+        ? { is_on: true }
+        : { nonce: m3ter.latestNonce, is_on: true };
+
+    console.log("[info] Enqueuing state:", state);
+
     enqueue(
       message["deviceInfo"]["devEui"],
-      encode(
-        (state ? state : { nonce: expectedNonce, is_on: true }) as State,
-        decoded.extensions.latitude ?? 0,
-        decoded.extensions.longitude ?? 0
-      )
+      encode(state as State, decoded.extensions.latitude ?? 0, decoded.extensions.longitude ?? 0)
     );
   } catch (error) {
     console.log(error);
diff --git a/src/store/sqlite.ts b/src/store/sqlite.ts
index 3cbe41d..5a0ad33 100644
--- a/src/store/sqlite.ts
+++ b/src/store/sqlite.ts
@@ -7,10 +7,12 @@ import { MeterRecord, TransactionRecord } from "../types";
 let db: DatabaseType;
 let insertMeterQuery: DatabaseStatementType;
 let getMeterByPublicKeyQuery: DatabaseStatementType;
+let getMeterByDevEuiQuery: DatabaseStatementType;
 let getMeterByTokenIdQuery: DatabaseStatementType;
 let getAllMetersQuery: DatabaseStatementType;
 let deleteMeterByPublicKeyQuery: DatabaseStatementType;
 let updateMeterNonceQuery: DatabaseStatementType;
+let updateMeterDevEuiQuery: DatabaseStatementType;
 // transaction queries
 let createTransactionQuery: DatabaseStatementType;
 let getTransactionByNonceQuery: DatabaseStatementType;
@@ -68,8 +70,11 @@ function initializeMetersTable() {
   return db.exec(`
         CREATE TABLE IF NOT EXISTS meters (
             publicKey TEXT,
+            devEui TEXT,
             tokenId INTEGER,
-            latestNonce INTEGER DEFAULT -1
+            latestNonce INTEGER DEFAULT -1,
+
+            UNIQUE(publicKey, tokenId)
         )
     `);
 }
@@ -78,20 +83,24 @@ function initializeMetersTable() {
 function prepareQueries() {
   // meter queries
   insertMeterQuery = db.prepare(`
-    INSERT OR REPLACE INTO meters (publicKey, tokenId, latestNonce)
-    VALUES (@publicKey, @tokenId, @latestNonce)
+    INSERT OR REPLACE INTO meters (publicKey, devEui, tokenId, latestNonce)
+    VALUES (@publicKey, @devEui, @tokenId, @latestNonce)
   `);
 
   getMeterByPublicKeyQuery = db.prepare(`
-    SELECT publicKey, tokenId, latestNonce FROM meters WHERE publicKey = ?
+    SELECT publicKey, devEui, tokenId, latestNonce FROM meters WHERE publicKey = ?
+  `);
+
+  getMeterByDevEuiQuery = db.prepare(`
+    SELECT publicKey, devEui, tokenId, latestNonce FROM meters WHERE devEui = ?
   `);
 
   getMeterByTokenIdQuery = db.prepare(`
-    SELECT publicKey, tokenId, latestNonce FROM meters WHERE tokenId = ?
+    SELECT publicKey, devEui, tokenId, latestNonce FROM meters WHERE tokenId = ?
   `);
 
   getAllMetersQuery = db.prepare(`
-    SELECT publicKey, tokenId, latestNonce FROM meters
+    SELECT publicKey, devEui, tokenId, latestNonce FROM meters
   `);
 
   deleteMeterByPublicKeyQuery = db.prepare(`
@@ -102,6 +111,10 @@ function prepareQueries() {
     UPDATE meters SET latestNonce = ? WHERE publicKey = ?
   `);
 
+  updateMeterDevEuiQuery = db.prepare(`
+    UPDATE meters SET devEui = ? WHERE publicKey = ?
+  `);
+
   // transaction queries
   createTransactionQuery = db.prepare(`
     INSERT INTO transactions (nonce, identifier, verified, receivedAt, raw)
@@ -134,6 +147,7 @@ export function saveMeter(meterData: MeterRecord): void {
       publicKey: meterData.publicKey,
       tokenId: meterData.tokenId,
       latestNonce: meterData.latestNonce,
+      devEui: meterData.devEui ?? null,
     });
   } catch (err: any) {
     console.error("Failed to save meter:", err);
@@ -151,6 +165,16 @@ export function getMeterByPublicKey(publicKey: string): MeterRecord | null {
   }
 }
 
+export function getMeterByDevEui(devEui: string): MeterRecord | null {
+  try {
+    const result = getMeterByDevEuiQuery.get(devEui) as MeterRecord | undefined;
+    return result || null;
+  } catch (err: any) {
+    console.error("Failed to get meter by DevEui:", err);
+    return null;
+  }
+}
+
 export function getMeterByTokenId(tokenId: string): MeterRecord | null {
   try {
     const result = getMeterByTokenIdQuery.get(tokenId) as MeterRecord | undefined;
@@ -199,15 +223,32 @@ export function updateMeterNonce(publicKey: string, nonce: number): boolean {
   }
 }
 
+export function updateMeterDevEui(publicKey: string, devEui: string): boolean {
+  try {
+    const result = updateMeterDevEuiQuery.run(devEui, publicKey);
+    const updated = result.changes > 0;
+    if (!updated) {
+      console.log("Meter not found for DevEui update:", { publicKey });
+    }
+    return updated;
+  } catch (err: any) {
+    console.error("Failed to update meter DevEui:", err);
+    return false;
+  }
+}
+
 // Transaction insertion function
 export function insertTransaction(transactionData: TransactionRecord): void {
   try {
-    const existingTransaction = getTransactionByNonceQuery.get(transactionData.nonce, transactionData.identifier) as TransactionRecord | undefined;
+    const existingTransaction = getTransactionByNonceQuery.get(
+      transactionData.nonce,
+      transactionData.identifier
+    ) as TransactionRecord | undefined;
 
     if (existingTransaction) {
       throw new Error(`Transaction with nonce ${transactionData.nonce} already exists`);
     }
-    
+
     transactionData.verified = +Boolean(transactionData.verified) as 0 | 1; // Ensure verified is set
     createTransactionQuery.run(transactionData);
   } catch (err: any) {
diff --git a/src/types.ts b/src/types.ts
index 0662823..2023423 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,6 +1,7 @@
 // Meter interface for database operations
 export interface MeterRecord {
   publicKey: string;
+  devEui: string | null; // Optional field for device EUI
   tokenId: number;
   latestNonce: number; // Optional field for tracking latest nonce
 }
diff --git a/tests/store/sqlite.test.ts b/tests/store/sqlite.test.ts
index 53f29ce..e2e0d13 100644
--- a/tests/store/sqlite.test.ts
+++ b/tests/store/sqlite.test.ts
@@ -10,6 +10,8 @@ import setupDatabase, {
   deleteVerifiedTransactionRecords,
   insertTransaction,
   deleteDatabase,
+  getMeterByDevEui,
+  updateMeterDevEui,
 } from "../../src/store/sqlite";
 
 beforeEach(() => {
@@ -28,11 +30,12 @@ it("should have no meters and transactions", () => {
   expect(transactions).toHaveLength(0);
 });
 
-it("should insert meter", () => {
+it("should insert meter without devEui", () => {
   const meterData = {
     publicKey: "test_public_key",
     tokenId: 1,
     latestNonce: 0,
+    devEui: null,
   };
   saveMeter(meterData);
 
@@ -40,11 +43,26 @@ it("should insert meter", () => {
   expect(meters).toHaveLength(1);
 });
 
+it("should insert meter with devEui", () => {
+  const meterData = {
+    publicKey: "test_public_key",
+    tokenId: 1,
+    latestNonce: 0,
+    devEui: "test_dev_eui",
+  };
+  saveMeter(meterData);
+
+  const meters = getAllMeterRecords();
+  expect(meters).toHaveLength(1);
+  expect(meters[0].devEui).toBe("test_dev_eui");
+});
+
 it("should get meter by public key", () => {
   const meterData = {
     publicKey: "test_public_key",
     tokenId: 1,
     latestNonce: 0,
+    devEui: "test_dev_eui",
   };
   saveMeter(meterData);
 
@@ -52,11 +70,26 @@ it("should get meter by public key", () => {
   expect(retrievedMeter).toEqual(meterData);
 });
 
+it("should get meter by device EUI", () => {
+  const meterData = {
+    publicKey: "test_public_key",
+    tokenId: 1,
+    latestNonce: 0,
+    devEui: "test_dev_eui",
+  };
+  saveMeter(meterData);
+
+  const retrievedMeter = getMeterByDevEui(meterData.devEui);
+  expect(retrievedMeter).toEqual(meterData);
+});
+
+
 it("should delete meter", () => {
   const meterData = {
     publicKey: "test_public_key",
     tokenId: 1,
     latestNonce: 0,
+    devEui: "test_dev_eui",
   };
   saveMeter(meterData);
   const deleted = deleteMeterByPublicKey(meterData.publicKey);
@@ -70,6 +103,7 @@ it("should update meter nonce", () => {
     publicKey: "test_public_key",
     tokenId: 1,
     latestNonce: 0,
+    devEui: "test_dev_eui",
   };
   saveMeter(meterData);
 
@@ -80,6 +114,22 @@ it("should update meter nonce", () => {
   expect(updatedMeter?.latestNonce).toBe(5);
 });
 
+it("should update meter devEui", () => {
+  const meterData = {
+    publicKey: "test_public_key",
+    tokenId: 1,
+    latestNonce: 0,
+    devEui: "test_dev_eui",
+  };
+  saveMeter(meterData);
+
+  const updated = updateMeterDevEui(meterData.publicKey, "new_dev_eui");
+  expect(updated).toBe(true);
+
+  const updatedMeter = getMeterByPublicKey(meterData.publicKey);
+  expect(updatedMeter?.devEui).toBe("new_dev_eui");
+});
+
 it("should insert transaction", () => {
   const transactionData = {
     nonce: 1,