diff --git a/packages/keyring-eth-hd/jest.config.js b/packages/keyring-eth-hd/jest.config.js
index a8cb232da..e5d1182c4 100644
--- a/packages/keyring-eth-hd/jest.config.js
+++ b/packages/keyring-eth-hd/jest.config.js
@@ -26,7 +26,7 @@ module.exports = merge(baseConfig, {
       branches: 83.87,
       functions: 100,
       lines: 95,
-      statements: 97.93,
+      statements: 97.91,
     },
   },
 });
diff --git a/packages/keyring-eth-hd/package.json b/packages/keyring-eth-hd/package.json
index fb7bb0714..8af3805f0 100644
--- a/packages/keyring-eth-hd/package.json
+++ b/packages/keyring-eth-hd/package.json
@@ -43,7 +43,7 @@
     "test:clean": "jest --clearCache"
   },
   "dependencies": {
-    "@ethereumjs/util": "^8.1.0",
+    "@ethereumjs/util": "^9.1.0",
     "@metamask/eth-sig-util": "^8.2.0",
     "@metamask/key-tree": "^10.0.2",
     "@metamask/scure-bip39": "^2.1.1",
@@ -51,7 +51,7 @@
     "ethereum-cryptography": "^2.1.2"
   },
   "devDependencies": {
-    "@ethereumjs/tx": "^4.2.0",
+    "@ethereumjs/tx": "^5.4.0",
     "@lavamoat/allow-scripts": "^3.2.1",
     "@lavamoat/preinstall-always-fail": "^2.1.0",
     "@metamask/auto-changelog": "^3.4.4",
diff --git a/packages/keyring-eth-hd/src/hd-keyring.test.ts b/packages/keyring-eth-hd/src/hd-keyring.test.ts
index 653357803..dc3d185b0 100644
--- a/packages/keyring-eth-hd/src/hd-keyring.test.ts
+++ b/packages/keyring-eth-hd/src/hd-keyring.test.ts
@@ -1,11 +1,9 @@
-import { TransactionFactory, Transaction as EthereumTx } from '@ethereumjs/tx';
 import {
-  isValidAddress,
-  bufferToHex,
-  toBuffer,
-  ecrecover,
-  pubToAddress,
-} from '@ethereumjs/util';
+  TransactionFactory,
+  LegacyTransaction,
+  type TypedTxData,
+} from '@ethereumjs/tx';
+import { isValidAddress, ecrecover, pubToAddress } from '@ethereumjs/util';
 import * as oldMMForkBIP39 from '@metamask/bip39';
 import {
   normalize,
@@ -22,7 +20,7 @@ import {
   type EIP7702Authorization,
 } from '@metamask/eth-sig-util';
 import { wordlist } from '@metamask/scure-bip39/dist/wordlists/english';
-import { assert, type Hex } from '@metamask/utils';
+import { assert, bytesToHex, hexToBytes, type Hex } from '@metamask/utils';
 import { webcrypto } from 'crypto';
 import { keccak256 } from 'ethereum-cryptography/keccak';
 // eslint-disable-next-line @typescript-eslint/naming-convention
@@ -642,7 +640,7 @@ describe('hd-keyring', () => {
         numberOfAccounts: 1,
       });
       const localMessage = 'hello there!';
-      const msgHashHex = bufferToHex(
+      const msgHashHex = bytesToHex(
         Buffer.from(keccak256(Buffer.from(localMessage))),
       );
       await keyring.addAccounts(9);
@@ -655,12 +653,12 @@ describe('hd-keyring', () => {
       signatures.forEach((sgn, index) => {
         const accountAddress = addresses[index];
 
-        const signatureR = toBuffer(sgn.slice(0, 66));
-        const signatureS = toBuffer(`0x${sgn.slice(66, 130)}`);
+        const signatureR = hexToBytes(sgn.slice(0, 66));
+        const signatureS = hexToBytes(`0x${sgn.slice(66, 130)}`);
         const signatureV = BigInt(`0x${sgn.slice(130, 132)}`);
-        const messageHash = toBuffer(msgHashHex);
+        const messageHash = hexToBytes(msgHashHex);
         const pub = ecrecover(messageHash, signatureV, signatureR, signatureS);
-        const adr = `0x${pubToAddress(pub).toString('hex')}`;
+        const adr = bytesToHex(pubToAddress(pub));
 
         expect(adr).toBe(accountAddress);
       });
@@ -1055,8 +1053,7 @@ describe('hd-keyring', () => {
       });
     });
 
-    const txParams = {
-      from: firstAcct,
+    const txParams: TypedTxData = {
       nonce: '0x00',
       gasPrice: '0x09184e72a000',
       gasLimit: '0x2710',
@@ -1065,7 +1062,7 @@ describe('hd-keyring', () => {
     };
 
     it('returns a signed legacy tx object', async function () {
-      const tx = new EthereumTx(txParams);
+      const tx = LegacyTransaction.fromTxData(txParams);
       expect(tx.isSigned()).toBe(false);
 
       const signed = await keyring.signTransaction(firstAcct, tx);
diff --git a/packages/keyring-eth-hd/src/hd-keyring.ts b/packages/keyring-eth-hd/src/hd-keyring.ts
index 0b2d46056..8511e9a83 100644
--- a/packages/keyring-eth-hd/src/hd-keyring.ts
+++ b/packages/keyring-eth-hd/src/hd-keyring.ts
@@ -1,11 +1,5 @@
 import type { TypedTransaction } from '@ethereumjs/tx';
-import {
-  privateToPublic,
-  publicToAddress,
-  ecsign,
-  arrToBufArr,
-  bufferToHex,
-} from '@ethereumjs/util';
+import { privateToPublic, publicToAddress, ecsign } from '@ethereumjs/util';
 import {
   concatSig,
   decrypt,
@@ -31,12 +25,13 @@ import {
   add0x,
   assert,
   assertIsHexString,
+  bigIntToBytes,
+  bytesToHex,
   type Hex,
   remove0x,
 } from '@metamask/utils';
 import { HDKey } from 'ethereum-cryptography/hdkey';
 import { keccak256 } from 'ethereum-cryptography/keccak';
-import { bytesToHex } from 'ethereum-cryptography/utils';
 
 // Options:
 const hdPathString = `m/44'/60'/0'/0`;
@@ -227,7 +222,7 @@ export class HdKeyring {
     });
     assert(wallet.publicKey, 'Expected public key to be set');
     const appKeyAddress = this.#normalizeAddress(
-      publicToAddress(wallet.publicKey).toString('hex'),
+      bytesToHex(publicToAddress(wallet.publicKey)),
     );
     return appKeyAddress;
   }
@@ -253,7 +248,7 @@ export class HdKeyring {
       privateKey instanceof Uint8Array,
       'Expected private key to be of type Uint8Array',
     );
-    return bytesToHex(privateKey);
+    return remove0x(bytesToHex(privateKey));
   }
 
   /**
@@ -293,10 +288,9 @@ export class HdKeyring {
     const privKey = this.#getPrivateKeyFor(address, opts);
     const msgSig = ecsign(Buffer.from(message, 'hex'), Buffer.from(privKey));
     const rawMsgSig = concatSig(
-      // WARN: verify this cast to Buffer
-      msgSig.v as unknown as Buffer,
-      msgSig.r,
-      msgSig.s,
+      Buffer.from(bigIntToBytes(msgSig.v)),
+      Buffer.from(msgSig.r),
+      Buffer.from(msgSig.s),
     );
     return rawMsgSig;
   }
@@ -425,7 +419,7 @@ export class HdKeyring {
     opts: HDKeyringAccountSelectionOptions = {},
   ): Promise<string> {
     const privKey = this.#getPrivateKeyFor(withAccount, opts);
-    const publicKey = getEncryptionPublicKey(bytesToHex(privKey));
+    const publicKey = getEncryptionPublicKey(remove0x(bytesToHex(privKey)));
     return publicKey;
   }
 
@@ -567,8 +561,8 @@ export class HdKeyring {
       assert(privateKey, 'Expected private key to be set');
       const appKeyOriginBuffer = Buffer.from(withAppKeyOrigin, 'utf8');
       const appKeyBuffer = Buffer.concat([privateKey, appKeyOriginBuffer]);
-      const appKeyPrivateKey = arrToBufArr(keccak256(appKeyBuffer));
-      const appKeyPublicKey = privateToPublic(appKeyPrivateKey);
+      const appKeyPrivateKey = Buffer.from(keccak256(appKeyBuffer));
+      const appKeyPublicKey = Buffer.from(privateToPublic(appKeyPrivateKey));
       return { privateKey: appKeyPrivateKey, publicKey: appKeyPublicKey };
     }
 
@@ -611,7 +605,7 @@ export class HdKeyring {
    */
   #addressfromPublicKey(publicKey: Uint8Array): Hex {
     return add0x(
-      bufferToHex(publicToAddress(Buffer.from(publicKey), true)).toLowerCase(),
+      bytesToHex(publicToAddress(Buffer.from(publicKey), true)).toLowerCase(),
     );
   }
 
diff --git a/packages/keyring-eth-ledger-bridge/package.json b/packages/keyring-eth-ledger-bridge/package.json
index 3fd5c1916..7bdb67f6d 100644
--- a/packages/keyring-eth-ledger-bridge/package.json
+++ b/packages/keyring-eth-ledger-bridge/package.json
@@ -47,14 +47,14 @@
   },
   "dependencies": {
     "@ethereumjs/rlp": "^5.0.2",
-    "@ethereumjs/tx": "^4.2.0",
-    "@ethereumjs/util": "^8.1.0",
+    "@ethereumjs/tx": "^5.4.0",
+    "@ethereumjs/util": "^9.1.0",
     "@ledgerhq/hw-app-eth": "^6.42.0",
     "@metamask/eth-sig-util": "^8.2.0",
     "hdkey": "^2.1.0"
   },
   "devDependencies": {
-    "@ethereumjs/common": "^3.2.0",
+    "@ethereumjs/common": "^4.4.0",
     "@lavamoat/allow-scripts": "^3.2.1",
     "@lavamoat/preinstall-always-fail": "^2.1.0",
     "@ledgerhq/hw-transport": "^6.31.3",
diff --git a/packages/keyring-eth-ledger-bridge/src/ledger-keyring.test.ts b/packages/keyring-eth-ledger-bridge/src/ledger-keyring.test.ts
index 0297a89be..18e8fbacd 100644
--- a/packages/keyring-eth-ledger-bridge/src/ledger-keyring.test.ts
+++ b/packages/keyring-eth-ledger-bridge/src/ledger-keyring.test.ts
@@ -3,7 +3,7 @@ import { RLP } from '@ethereumjs/rlp';
 import { TransactionFactory } from '@ethereumjs/tx';
 import * as ethUtil from '@ethereumjs/util';
 import * as sigUtil from '@metamask/eth-sig-util';
-import { Hex } from '@metamask/utils';
+import { bytesToHex, Hex } from '@metamask/utils';
 import EthereumTx from 'ethereumjs-tx';
 import HDKey from 'hdkey';
 
@@ -49,7 +49,7 @@ const fakeTx = new EthereumTx({
   value: '0x00',
   data: '0x7f7465737432000000000000000000000000000000000000000000000000000000600057',
   // EIP 155 chainId - mainnet: 1, ropsten: 3
-  chainId: 1,
+  chainId: '0x1',
 });
 
 const common = new Common({ chain: Chain.Mainnet, hardfork: Hardfork.Berlin });
@@ -646,7 +646,7 @@ describe('LedgerKeyring', function () {
             v: '0x26',
             r: '0xf3a7718999d1b87beda810b25cc025153e74df0745279826b9b2f3d1d1b6318',
             s: '0x7e33bdfbf5272dc4f55649e9ba729849670171a68ef8c0fbeed3b879b90b8954',
-          };
+          } as const;
 
           await basicSetupToUnlockOneAccount();
 
@@ -672,7 +672,7 @@ describe('LedgerKeyring', function () {
               expect(params).toStrictEqual({
                 hdPath: "m/44'/60'/0'/0",
                 tx: Buffer.from(
-                  RLP.encode(newFakeTx.getMessageToSign(false)),
+                  RLP.encode(newFakeTx.getMessageToSign()),
                 ).toString('hex'),
               });
               return expectedRSV;
@@ -694,7 +694,7 @@ describe('LedgerKeyring', function () {
             v: '0x0',
             r: '0x5ffb3adeaec80e430e7a7b02d95c5108b6f09a0bdf3cf69869dc1b38d0fb8d3a',
             s: '0x28b234a5403d31564e18258df84c51a62683e3f54fa2b106fdc1a9058006a112',
-          };
+          } as const;
 
           await basicSetupToUnlockOneAccount();
 
@@ -719,7 +719,7 @@ describe('LedgerKeyring', function () {
             .mockImplementation(async (params) => {
               expect(params).toStrictEqual({
                 hdPath: "m/44'/60'/0'/0",
-                tx: fakeTypeTwoTx.getMessageToSign(false).toString('hex'),
+                tx: bytesToHex(fakeTypeTwoTx.getMessageToSign() as Uint8Array),
               });
               return expectedRSV;
             });
diff --git a/packages/keyring-eth-ledger-bridge/src/ledger-keyring.ts b/packages/keyring-eth-ledger-bridge/src/ledger-keyring.ts
index 4155a3843..ab123efdb 100644
--- a/packages/keyring-eth-ledger-bridge/src/ledger-keyring.ts
+++ b/packages/keyring-eth-ledger-bridge/src/ledger-keyring.ts
@@ -1,6 +1,10 @@
 import { RLP } from '@ethereumjs/rlp';
-import { TransactionFactory, TxData, TypedTransaction } from '@ethereumjs/tx';
-import { bufferToHex, publicToAddress } from '@ethereumjs/util';
+import {
+  TransactionFactory,
+  TypedTxData,
+  type TypedTransaction,
+} from '@ethereumjs/tx';
+import { publicToAddress } from '@ethereumjs/util';
 import type { MessageTypes, TypedMessage } from '@metamask/eth-sig-util';
 import {
   recoverPersonalSignature,
@@ -9,7 +13,13 @@ import {
   TypedDataUtils,
 } from '@metamask/eth-sig-util';
 import type { Keyring } from '@metamask/keyring-utils';
-import { add0x, getChecksumAddress, Hex, remove0x } from '@metamask/utils';
+import {
+  add0x,
+  bytesToHex,
+  getChecksumAddress,
+  Hex,
+  remove0x,
+} from '@metamask/utils';
 import { Buffer } from 'buffer';
 import type OldEthJsTransaction from 'ethereumjs-tx';
 import HDKey from 'hdkey';
@@ -216,7 +226,7 @@ export class LedgerKeyring implements Keyring {
       // we return the checksummed address of the public key stored in
       // `this.hdk`, which is the root address of the last unlocked path.
       return this.#getChecksumHexAddress(
-        publicToAddress(this.hdk.publicKey, true).toString('hex'),
+        bytesToHex(publicToAddress(this.hdk.publicKey, true)),
       );
     }
     const path = hdPath ? this.#toLedgerPath(hdPath) : this.hdPath;
@@ -333,8 +343,7 @@ export class LedgerKeyring implements Keyring {
       // transaction which is only communicated to ethereumjs-tx in this
       // value. In newer versions the chainId is communicated via the 'Common'
       // object.
-      // @ts-expect-error tx.v should be a Buffer, but we are assigning a string
-      tx.v = bufferToHex(tx.getChainId());
+      tx.v = tx.getChainId();
       // @ts-expect-error tx.r should be a Buffer, but we are assigning a string
       tx.r = '0x00';
       // @ts-expect-error tx.s should be a Buffer, but we are assigning a string
@@ -358,17 +367,17 @@ export class LedgerKeyring implements Keyring {
     // Note also that `getMessageToSign` will return valid RLP for all transaction types, whereas the
     // `serialize` method will not for any transaction type except legacy. This is because `serialize` includes
     // empty r, s and v values in the encoded rlp. This is why we use `getMessageToSign` here instead of `serialize`.
-    const messageToSign = tx.getMessageToSign(false);
+    const messageToSign = tx.getMessageToSign();
 
-    rawTxHex = Buffer.isBuffer(messageToSign)
-      ? messageToSign.toString('hex')
-      : Buffer.from(RLP.encode(messageToSign)).toString('hex');
+    rawTxHex = Array.isArray(messageToSign)
+      ? Buffer.from(RLP.encode(messageToSign)).toString('hex')
+      : bytesToHex(messageToSign);
 
     return this.#signTransaction(address, rawTxHex, (payload) => {
       // Because tx will be immutable, first get a plain javascript object that
       // represents the transaction. Using txData here as it aligns with the
       // nomenclature of ethereumjs/tx.
-      const txData: TxData = tx.toJSON();
+      const txData: TypedTxData = tx.toJSON();
       // The fromTxData utility expects a type to support transactions with a type other than 0
       txData.type = tx.type;
       // The fromTxData utility expects v,r and s to be hex prefixed
@@ -632,8 +641,8 @@ export class LedgerKeyring implements Keyring {
 
   #addressFromIndex(basePath: string, i: number): Hex {
     const dkey = this.hdk.derive(`${basePath}/${i}`);
-    const address = publicToAddress(dkey.publicKey, true).toString('hex');
-    return this.#getChecksumHexAddress(add0x(address));
+    const address = bytesToHex(publicToAddress(dkey.publicKey, true));
+    return this.#getChecksumHexAddress(address);
   }
 
   #pathFromAddress(address: string): string {
diff --git a/packages/keyring-eth-simple/package.json b/packages/keyring-eth-simple/package.json
index 80af4beec..d2218450f 100644
--- a/packages/keyring-eth-simple/package.json
+++ b/packages/keyring-eth-simple/package.json
@@ -44,14 +44,14 @@
     "test:watch": "jest --watch"
   },
   "dependencies": {
-    "@ethereumjs/util": "^8.1.0",
+    "@ethereumjs/util": "^9.1.0",
     "@metamask/eth-sig-util": "^8.2.0",
     "@metamask/utils": "^11.1.0",
     "ethereum-cryptography": "^2.1.2",
     "randombytes": "^2.1.0"
   },
   "devDependencies": {
-    "@ethereumjs/tx": "^4.2.0",
+    "@ethereumjs/tx": "^5.4.0",
     "@lavamoat/allow-scripts": "^3.2.1",
     "@lavamoat/preinstall-always-fail": "^2.1.0",
     "@metamask/auto-changelog": "^3.4.4",
diff --git a/packages/keyring-eth-simple/src/simple-keyring.test.ts b/packages/keyring-eth-simple/src/simple-keyring.test.ts
index 6a35b429e..3eaab107f 100644
--- a/packages/keyring-eth-simple/src/simple-keyring.test.ts
+++ b/packages/keyring-eth-simple/src/simple-keyring.test.ts
@@ -1,12 +1,14 @@
-import { Transaction as EthereumTx, TransactionFactory } from '@ethereumjs/tx';
 import {
-  bufferToHex,
+  LegacyTransaction,
+  TransactionFactory,
+  TypedTxData,
+} from '@ethereumjs/tx';
+import {
   ecrecover,
   isValidAddress,
   privateToAddress,
   pubToAddress,
   stripHexPrefix,
-  toBuffer,
 } from '@ethereumjs/util';
 import {
   EIP7702Authorization,
@@ -21,7 +23,7 @@ import {
   SignTypedDataVersion,
   TypedMessage,
 } from '@metamask/eth-sig-util';
-import { add0x, Hex } from '@metamask/utils';
+import { add0x, bytesToHex, Hex, hexToBytes } from '@metamask/utils';
 import assert from 'assert';
 import { keccak256 } from 'ethereum-cryptography/keccak';
 // eslint-disable-next-line @typescript-eslint/naming-convention
@@ -101,8 +103,7 @@ describe('simple-keyring', function () {
     const address = '0x9858e7d8b79fc3e6d989636721584498926da38a';
     const privateKey =
       '0x7dd98753d7b4394095de7d176c58128e2ed6ee600abe97c9f6d9fd65015d9b18';
-    const txParams = {
-      from: address,
+    const txParams: TypedTxData = {
       nonce: '0x00',
       gasPrice: '0x09184e72a000',
       gasLimit: '0x2710',
@@ -112,7 +113,7 @@ describe('simple-keyring', function () {
 
     it('returns a signed legacy tx object (using @ethereumjs/tx)', async function () {
       await keyring.deserialize([privateKey]);
-      const tx = new EthereumTx(txParams);
+      const tx = LegacyTransaction.fromTxData(txParams);
       expect(tx.isSigned()).toBe(false);
 
       const signed = await keyring.signTransaction(address, tx);
@@ -177,9 +178,7 @@ describe('simple-keyring', function () {
     it('reliably can decode messages it signs', async function () {
       await keyring.deserialize([privateKey]);
       const localMessage = 'hello there!';
-      const msgHashHex = bufferToHex(
-        Buffer.from(keccak256(Buffer.from(localMessage))),
-      );
+      const msgHashHex = bytesToHex(keccak256(Buffer.from(localMessage)));
 
       await keyring.addAccounts(9);
       const addresses = await keyring.getAccounts();
@@ -192,14 +191,14 @@ describe('simple-keyring', function () {
         const accountAddress = addresses[index];
 
         /* eslint-disable id-length */
-        const r = toBuffer(sgn.slice(0, 66));
-        const s = toBuffer(`0x${sgn.slice(66, 130)}`);
+        const r = hexToBytes(sgn.slice(0, 66));
+        const s = hexToBytes(`0x${sgn.slice(66, 130)}`);
         const v = BigInt(`0x${sgn.slice(130, 132)}`);
-        const m = toBuffer(msgHashHex);
+        const m = hexToBytes(msgHashHex);
         /* eslint-enable id-length */
 
         const pub = ecrecover(m, v, r, s);
-        const adr = `0x${pubToAddress(pub).toString('hex')}`;
+        const adr = bytesToHex(pubToAddress(pub));
 
         expect(adr).toBe(accountAddress);
       });
@@ -296,7 +295,7 @@ describe('simple-keyring', function () {
       '6969696969696969696969696969696969696969696969696969696969696969',
       'hex',
     );
-    const privKeyHex = bufferToHex(privateKey);
+    const privKeyHex = bytesToHex(privateKey);
     const message = '0x68656c6c6f20776f726c64';
     const expectedSignature =
       '0xce909e8ea6851bc36c007a0072d0524b07a3ff8d4e623aca4c71ca8e57250c4d0a3fc38fa8fbaaa81ead4b9f6bd03356b6f8bf18bccad167d78891636e1d69561b';
@@ -550,9 +549,7 @@ describe('simple-keyring', function () {
     const address = '0x29c76e6ad8f28bb1004902578fb108c507be341b';
     const privKeyHex =
       '0x4af1bceebf7f3634ec3cff8a2c38e51178d5d4ce585c52d6043e5e2cc3418bb0';
-    const signerAddress = `0x${privateToAddress(
-      Buffer.from(privKeyHex.slice(2), 'hex'),
-    ).toString('hex')}`;
+    const signerAddress = bytesToHex(privateToAddress(hexToBytes(privKeyHex)));
 
     const chainId = 1;
     const nonce = 1;
@@ -593,14 +590,11 @@ describe('simple-keyring', function () {
 
   describe('#decryptMessage', function () {
     const address = '0xbe93f9bacbcffc8ee6663f2647917ed7a20a57bb';
-    const privateKey = Buffer.from(
-      '6969696969696969696969696969696969696969696969696969696969696969',
-      'hex',
-    );
-    const privKeyHex = bufferToHex(privateKey);
+    const privKeyHex =
+      '6969696969696969696969696969696969696969696969696969696969696969';
     const message = 'Hello world!';
     const encryptedMessage = encrypt({
-      publicKey: getEncryptionPublicKey(privateKey.toString('hex')),
+      publicKey: getEncryptionPublicKey(privKeyHex),
       data: message,
       version: 'x25519-xsalsa20-poly1305',
     });
@@ -633,12 +627,9 @@ describe('simple-keyring', function () {
 
   describe('#encryptionPublicKey', function () {
     const address = '0xbe93f9bacbcffc8ee6663f2647917ed7a20a57bb';
-    const privateKey = Buffer.from(
-      '6969696969696969696969696969696969696969696969696969696969696969',
-      'hex',
-    );
+    const privKeyHex =
+      '0x6969696969696969696969696969696969696969696969696969696969696969';
     const publicKey = 'GxuMqoE2oHsZzcQtv/WMNB3gCH2P6uzynuwO1P0MM1U=';
-    const privKeyHex = bufferToHex(privateKey);
 
     it('returns the expected value', async function () {
       await keyring.deserialize([privKeyHex]);
diff --git a/packages/keyring-eth-simple/src/simple-keyring.ts b/packages/keyring-eth-simple/src/simple-keyring.ts
index 8b7410bdc..ff0ee7b6b 100644
--- a/packages/keyring-eth-simple/src/simple-keyring.ts
+++ b/packages/keyring-eth-simple/src/simple-keyring.ts
@@ -1,13 +1,10 @@
 import { TypedTransaction } from '@ethereumjs/tx';
 import {
-  arrToBufArr,
-  bufferToHex,
   ecsign,
   isValidPrivate,
   privateToPublic,
   publicToAddress,
   stripHexPrefix,
-  toBuffer,
 } from '@ethereumjs/util';
 import {
   concatSig,
@@ -21,7 +18,13 @@ import {
   SignTypedDataVersion,
 } from '@metamask/eth-sig-util';
 import { Keyring } from '@metamask/keyring-utils';
-import { add0x, Eip1024EncryptedData, Hex } from '@metamask/utils';
+import {
+  add0x,
+  bigIntToBytes,
+  bytesToHex,
+  Eip1024EncryptedData,
+  Hex,
+} from '@metamask/utils';
 import { keccak256 } from 'ethereum-cryptography/keccak';
 import randombytes from 'randombytes';
 
@@ -63,7 +66,7 @@ export default class SimpleKeyring implements Keyring {
     this.#wallets = privateKeys.map((hexPrivateKey) => {
       const strippedHexPrivateKey = stripHexPrefix(hexPrivateKey);
       const privateKey = Buffer.from(strippedHexPrivateKey, 'hex');
-      const publicKey = privateToPublic(privateKey);
+      const publicKey = Buffer.from(privateToPublic(privateKey));
       return { privateKey, publicKey };
     });
   }
@@ -72,19 +75,19 @@ export default class SimpleKeyring implements Keyring {
     const newWallets = [];
     for (let i = 0; i < numAccounts; i++) {
       const privateKey = generateKey();
-      const publicKey = privateToPublic(privateKey);
+      const publicKey = Buffer.from(privateToPublic(privateKey));
       newWallets.push({ privateKey, publicKey });
     }
     this.#wallets = this.#wallets.concat(newWallets);
     const hexWallets = newWallets.map(({ publicKey }) =>
-      add0x(bufferToHex(publicToAddress(publicKey))),
+      add0x(bytesToHex(publicToAddress(publicKey))),
     );
     return hexWallets;
   }
 
   async getAccounts(): Promise<Hex[]> {
     return this.#wallets.map(({ publicKey }) =>
-      add0x(bufferToHex(publicToAddress(publicKey))),
+      add0x(bytesToHex(publicToAddress(publicKey))),
     );
   }
 
@@ -123,7 +126,11 @@ export default class SimpleKeyring implements Keyring {
     }
     const privKey = this.#getPrivateKeyFor(address, opts);
     const msgSig = ecsign(Buffer.from(message, 'hex'), privKey);
-    const rawMsgSig = concatSig(toBuffer(msgSig.v), msgSig.r, msgSig.s);
+    const rawMsgSig = concatSig(
+      Buffer.from(bigIntToBytes(msgSig.v)),
+      Buffer.from(msgSig.r),
+      Buffer.from(msgSig.s),
+    );
     return rawMsgSig;
   }
 
@@ -193,7 +200,7 @@ export default class SimpleKeyring implements Keyring {
     const wallet = this.#getWalletForAccount(address, {
       withAppKeyOrigin: origin,
     });
-    const appKeyAddress = add0x(bufferToHex(publicToAddress(wallet.publicKey)));
+    const appKeyAddress = add0x(bytesToHex(publicToAddress(wallet.publicKey)));
     return appKeyAddress;
   }
 
@@ -210,7 +217,7 @@ export default class SimpleKeyring implements Keyring {
     if (
       !this.#wallets
         .map(({ publicKey }) =>
-          bufferToHex(publicToAddress(publicKey)).toLowerCase(),
+          bytesToHex(publicToAddress(publicKey)).toLowerCase(),
         )
         .includes(address.toLowerCase())
     ) {
@@ -219,7 +226,7 @@ export default class SimpleKeyring implements Keyring {
 
     this.#wallets = this.#wallets.filter(
       ({ publicKey }) =>
-        bufferToHex(publicToAddress(publicKey)).toLowerCase() !==
+        bytesToHex(publicToAddress(publicKey)).toLowerCase() !==
         address.toLowerCase(),
     );
   }
@@ -230,7 +237,7 @@ export default class SimpleKeyring implements Keyring {
   ): Wallet {
     const address = normalize(account);
     let wallet = this.#wallets.find(
-      ({ publicKey }) => bufferToHex(publicToAddress(publicKey)) === address,
+      ({ publicKey }) => bytesToHex(publicToAddress(publicKey)) === address,
     );
     if (!wallet) {
       throw new Error('Simple Keyring - Unable to find matching address.');
@@ -240,9 +247,12 @@ export default class SimpleKeyring implements Keyring {
       const { privateKey } = wallet;
       const appKeyOriginBuffer = Buffer.from(opts.withAppKeyOrigin, 'utf8');
       const appKeyBuffer = Buffer.concat([privateKey, appKeyOriginBuffer]);
-      const appKeyPrivateKey = arrToBufArr(keccak256(appKeyBuffer));
+      const appKeyPrivateKey = keccak256(appKeyBuffer);
       const appKeyPublicKey = privateToPublic(appKeyPrivateKey);
-      wallet = { privateKey: appKeyPrivateKey, publicKey: appKeyPublicKey };
+      wallet = {
+        privateKey: Buffer.from(appKeyPrivateKey),
+        publicKey: Buffer.from(appKeyPublicKey),
+      };
     }
 
     return wallet;
diff --git a/packages/keyring-eth-trezor/jest.config.js b/packages/keyring-eth-trezor/jest.config.js
index c7c45a072..34ecf6872 100644
--- a/packages/keyring-eth-trezor/jest.config.js
+++ b/packages/keyring-eth-trezor/jest.config.js
@@ -23,7 +23,7 @@ module.exports = merge(baseConfig, {
   // An object that configures minimum threshold enforcement for coverage results
   coverageThreshold: {
     global: {
-      branches: 48.24,
+      branches: 51.63,
       functions: 91.22,
       lines: 90.1,
       statements: 90.3,
diff --git a/packages/keyring-eth-trezor/package.json b/packages/keyring-eth-trezor/package.json
index 186dedd2a..b49083765 100644
--- a/packages/keyring-eth-trezor/package.json
+++ b/packages/keyring-eth-trezor/package.json
@@ -46,8 +46,8 @@
     "test:watch": "jest --watch"
   },
   "dependencies": {
-    "@ethereumjs/tx": "^4.2.0",
-    "@ethereumjs/util": "^8.1.0",
+    "@ethereumjs/tx": "^5.4.0",
+    "@ethereumjs/util": "^9.1.0",
     "@metamask/eth-sig-util": "^8.2.0",
     "@metamask/utils": "^11.1.0",
     "@trezor/connect-plugin-ethereum": "^9.0.3",
@@ -56,7 +56,7 @@
     "tslib": "^2.6.2"
   },
   "devDependencies": {
-    "@ethereumjs/common": "^3.2.0",
+    "@ethereumjs/common": "^4.4.0",
     "@lavamoat/allow-scripts": "^3.2.1",
     "@lavamoat/preinstall-always-fail": "^2.1.0",
     "@metamask/auto-changelog": "^3.4.4",
diff --git a/packages/keyring-eth-trezor/src/trezor-keyring.test.ts b/packages/keyring-eth-trezor/src/trezor-keyring.test.ts
index ca8120dca..2747b5079 100644
--- a/packages/keyring-eth-trezor/src/trezor-keyring.test.ts
+++ b/packages/keyring-eth-trezor/src/trezor-keyring.test.ts
@@ -412,7 +412,9 @@ describe('TrezorKeyring', function () {
       sinon.stub(fakeTx, 'verifySignature').callsFake(() => true);
       sinon
         .stub(fakeTx, 'getSenderAddress')
-        .callsFake(() => Address.fromString(fakeAccounts[0]).toBuffer());
+        .callsFake(() =>
+          Buffer.from(Address.fromString(fakeAccounts[0]).bytes),
+        );
 
       const returnedTx = await keyring.signTransaction(fakeAccounts[0], fakeTx);
       // assert that the v,r,s values got assigned to tx.
@@ -533,6 +535,7 @@ describe('TrezorKeyring', function () {
       sinon.assert.calledWithExactly(ethereumSignTransactionStub, {
         path: "m/44'/60'/0'/0/0",
         transaction: {
+          type: '0x2',
           chainId: 1,
           nonce: '0x0',
           maxPriorityFeePerGas: '0x9184e72a000',
diff --git a/packages/keyring-eth-trezor/src/trezor-keyring.ts b/packages/keyring-eth-trezor/src/trezor-keyring.ts
index 203864c1c..7d1fe5dfd 100644
--- a/packages/keyring-eth-trezor/src/trezor-keyring.ts
+++ b/packages/keyring-eth-trezor/src/trezor-keyring.ts
@@ -1,13 +1,19 @@
 import { TransactionFactory } from '@ethereumjs/tx';
-import type { TypedTransaction, TxData } from '@ethereumjs/tx';
-import { bufferToHex, publicToAddress, toBuffer } from '@ethereumjs/util';
+import type { TypedTransaction, TypedTxData } from '@ethereumjs/tx';
+import { publicToAddress, toChecksumAddress } from '@ethereumjs/util';
 import {
   TypedMessage,
   SignTypedDataVersion,
   MessageTypes,
 } from '@metamask/eth-sig-util';
 import type { Keyring } from '@metamask/keyring-utils';
-import { add0x, getChecksumAddress, Hex, remove0x } from '@metamask/utils';
+import {
+  add0x,
+  bytesToHex,
+  getChecksumAddress,
+  Hex,
+  remove0x,
+} from '@metamask/utils';
 import { transformTypedData } from '@trezor/connect-plugin-ethereum';
 import type {
   EthereumTransactionEIP1559,
@@ -317,7 +323,7 @@ export class TrezorKeyring implements Keyring {
         // Because tx will be immutable, first get a plain javascript object that
         // represents the transaction. Using txData here as it aligns with the
         // nomenclature of ethereumjs/tx.
-        const txData: TxData = tx.toJSON();
+        const txData: TypedTxData = tx.toJSON();
         // The fromTxData utility expects a type to support transactions with a type other than 0
         txData.type = tx.type;
         // The fromTxData utility expects v,r and s to be hex prefixed
@@ -369,7 +375,7 @@ export class TrezorKeyring implements Keyring {
       transaction = {
         ...tx.toJSON(),
         chainId,
-        to: this.#normalize(toBuffer(tx.to)),
+        to: this.#normalize(Buffer.from(tx.to?.bytes ?? [])),
       } as EthereumTransaction | EthereumTransactionEIP1559;
     }
 
@@ -542,13 +548,13 @@ export class TrezorKeyring implements Keyring {
   }
 
   #normalize(buf: Buffer): string {
-    return bufferToHex(buf).toString();
+    return bytesToHex(buf);
   }
 
   #addressFromIndex(basePath: string, i: number): Hex {
     const dkey = this.hdk.derive(`${basePath}/${i}`);
-    const address = publicToAddress(dkey.publicKey, true).toString('hex');
-    return getChecksumAddress(add0x(address));
+    const address = bytesToHex(publicToAddress(dkey.publicKey, true));
+    return toChecksumAddress(address);
   }
 
   #pathFromAddress(address: Hex): string {
diff --git a/packages/keyring-snap-bridge/package.json b/packages/keyring-snap-bridge/package.json
index e14ece275..1dd0a5581 100644
--- a/packages/keyring-snap-bridge/package.json
+++ b/packages/keyring-snap-bridge/package.json
@@ -37,7 +37,7 @@
     "test:watch": "jest --watch"
   },
   "dependencies": {
-    "@ethereumjs/tx": "^4.2.0",
+    "@ethereumjs/tx": "^5.4.0",
     "@metamask/base-controller": "^7.1.1",
     "@metamask/eth-sig-util": "^8.2.0",
     "@metamask/keyring-api": "workspace:^",
diff --git a/packages/keyring-snap-bridge/src/SnapKeyring.test.ts b/packages/keyring-snap-bridge/src/SnapKeyring.test.ts
index 1f430fcf9..dad31de48 100644
--- a/packages/keyring-snap-bridge/src/SnapKeyring.test.ts
+++ b/packages/keyring-snap-bridge/src/SnapKeyring.test.ts
@@ -1,4 +1,4 @@
-import { TransactionFactory } from '@ethereumjs/tx';
+import { TransactionFactory, type TypedTxData } from '@ethereumjs/tx';
 import { Messenger } from '@metamask/base-controller';
 import { SignTypedDataVersion } from '@metamask/eth-sig-util';
 import type {
@@ -838,7 +838,7 @@ describe('SnapKeyring', () => {
         expect(keyring.listAccounts()[0]?.methods).toStrictEqual(
           updatedMethods,
         );
-        const mockTx = {
+        const mockTx: TypedTxData = {
           data: '0x0',
           gasLimit: '0x26259fe',
           gasPrice: '0x1',
@@ -1343,7 +1343,7 @@ describe('SnapKeyring', () => {
 
   describe('signTransaction', () => {
     it('signs a ethereum transaction synchronously', async () => {
-      const mockTx = {
+      const mockTx: TypedTxData = {
         data: '0x00',
         gasLimit: '0x26259fe',
         gasPrice: '0x1',
@@ -1353,7 +1353,7 @@ describe('SnapKeyring', () => {
         chainId: '0x1',
         type: '0x0',
       };
-      const mockSignedTx = {
+      const mockSignedTx: TypedTxData = {
         ...mockTx,
         r: '0x0',
         s: '0x0',
diff --git a/packages/keyring-snap-bridge/src/SnapKeyring.ts b/packages/keyring-snap-bridge/src/SnapKeyring.ts
index dcf652956..aafff6da9 100644
--- a/packages/keyring-snap-bridge/src/SnapKeyring.ts
+++ b/packages/keyring-snap-bridge/src/SnapKeyring.ts
@@ -36,7 +36,7 @@ import { strictMask } from '@metamask/keyring-utils';
 import type { SnapId } from '@metamask/snaps-sdk';
 import { type Snap } from '@metamask/snaps-utils';
 import { assert, mask, object, string } from '@metamask/superstruct';
-import type { Json } from '@metamask/utils';
+import type { Hex, Json } from '@metamask/utils';
 import {
   bigIntToHex,
   KnownCaipNamespace,
@@ -963,9 +963,9 @@ export class SnapKeyring extends EventEmitter {
 
     return TransactionFactory.fromTxData({
       ...(tx as Record<string, Json>),
-      r: signature.r,
-      s: signature.s,
-      v: signature.v,
+      r: signature.r as Hex,
+      s: signature.s as Hex,
+      v: signature.v as Hex,
     });
   }
 
diff --git a/packages/keyring-utils/package.json b/packages/keyring-utils/package.json
index c93eef156..ec4a3a0cb 100644
--- a/packages/keyring-utils/package.json
+++ b/packages/keyring-utils/package.json
@@ -45,7 +45,7 @@
     "test:watch": "jest --watch"
   },
   "dependencies": {
-    "@ethereumjs/tx": "^4.2.0",
+    "@ethereumjs/tx": "^5.4.0",
     "@metamask/superstruct": "^3.1.0",
     "@metamask/utils": "^11.1.0",
     "bitcoin-address-validation": "^2.2.3"
diff --git a/packages/keyring-utils/src/keyring.ts b/packages/keyring-utils/src/keyring.ts
index a523e3cee..8be5157d3 100644
--- a/packages/keyring-utils/src/keyring.ts
+++ b/packages/keyring-utils/src/keyring.ts
@@ -1,4 +1,4 @@
-import type { TypedTransaction, TxData } from '@ethereumjs/tx';
+import type { TypedTransaction, TypedTxData } from '@ethereumjs/tx';
 import type { Eip1024EncryptedData, Hex, Json } from '@metamask/utils';
 
 /**
@@ -140,7 +140,7 @@ export type Keyring = {
     address: Hex,
     transaction: TypedTransaction,
     options?: Record<string, unknown>,
-  ): Promise<TxData>;
+  ): Promise<TypedTxData>;
 
   /**
    * Sign a message. This is equivalent to an older version of the the
diff --git a/yarn.lock b/yarn.lock
index f7aa80eae..ba9a48aa4 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -643,7 +643,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@ethereumjs/tx@npm:^5.2.1":
+"@ethereumjs/tx@npm:^5.2.1, @ethereumjs/tx@npm:^5.4.0":
   version: 5.4.0
   resolution: "@ethereumjs/tx@npm:5.4.0"
   dependencies:
@@ -1661,8 +1661,8 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@metamask/eth-hd-keyring@workspace:packages/keyring-eth-hd"
   dependencies:
-    "@ethereumjs/tx": "npm:^4.2.0"
-    "@ethereumjs/util": "npm:^8.1.0"
+    "@ethereumjs/tx": "npm:^5.4.0"
+    "@ethereumjs/util": "npm:^9.1.0"
     "@lavamoat/allow-scripts": "npm:^3.2.1"
     "@lavamoat/preinstall-always-fail": "npm:^2.1.0"
     "@metamask/auto-changelog": "npm:^3.4.4"
@@ -1684,10 +1684,10 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@metamask/eth-ledger-bridge-keyring@workspace:packages/keyring-eth-ledger-bridge"
   dependencies:
-    "@ethereumjs/common": "npm:^3.2.0"
+    "@ethereumjs/common": "npm:^4.4.0"
     "@ethereumjs/rlp": "npm:^5.0.2"
-    "@ethereumjs/tx": "npm:^4.2.0"
-    "@ethereumjs/util": "npm:^8.1.0"
+    "@ethereumjs/tx": "npm:^5.4.0"
+    "@ethereumjs/util": "npm:^9.1.0"
     "@lavamoat/allow-scripts": "npm:^3.2.1"
     "@lavamoat/preinstall-always-fail": "npm:^2.1.0"
     "@ledgerhq/hw-app-eth": "npm:^6.42.0"
@@ -1760,8 +1760,8 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@metamask/eth-simple-keyring@workspace:packages/keyring-eth-simple"
   dependencies:
-    "@ethereumjs/tx": "npm:^4.2.0"
-    "@ethereumjs/util": "npm:^8.1.0"
+    "@ethereumjs/tx": "npm:^5.4.0"
+    "@ethereumjs/util": "npm:^9.1.0"
     "@lavamoat/allow-scripts": "npm:^3.2.1"
     "@lavamoat/preinstall-always-fail": "npm:^2.1.0"
     "@metamask/auto-changelog": "npm:^3.4.4"
@@ -1790,7 +1790,7 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@metamask/eth-snap-keyring@workspace:packages/keyring-snap-bridge"
   dependencies:
-    "@ethereumjs/tx": "npm:^4.2.0"
+    "@ethereumjs/tx": "npm:^5.4.0"
     "@lavamoat/allow-scripts": "npm:^3.2.1"
     "@lavamoat/preinstall-always-fail": "npm:^2.1.0"
     "@metamask/auto-changelog": "npm:^3.4.4"
@@ -1828,9 +1828,9 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@metamask/eth-trezor-keyring@workspace:packages/keyring-eth-trezor"
   dependencies:
-    "@ethereumjs/common": "npm:^3.2.0"
-    "@ethereumjs/tx": "npm:^4.2.0"
-    "@ethereumjs/util": "npm:^8.1.0"
+    "@ethereumjs/common": "npm:^4.4.0"
+    "@ethereumjs/tx": "npm:^5.4.0"
+    "@ethereumjs/util": "npm:^9.1.0"
     "@lavamoat/allow-scripts": "npm:^3.2.1"
     "@lavamoat/preinstall-always-fail": "npm:^2.1.0"
     "@metamask/auto-changelog": "npm:^3.4.4"
@@ -2063,7 +2063,7 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@metamask/keyring-utils@workspace:packages/keyring-utils"
   dependencies:
-    "@ethereumjs/tx": "npm:^4.2.0"
+    "@ethereumjs/tx": "npm:^5.4.0"
     "@lavamoat/allow-scripts": "npm:^3.2.1"
     "@lavamoat/preinstall-always-fail": "npm:^2.1.0"
     "@metamask/auto-changelog": "npm:^3.4.4"