diff --git a/CHANGELOG.md b/CHANGELOG.md
index d348a85..04ec6c8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 # Changelog
 
 ## Unreleased
+- Preserve the sign of positive EIP-712 signed integers supplied as JavaScript numbers.
 - Reset unfinished sessions when connecting to firmware v9.28.0 or newer, allowing host
   reconnects while the device remains powered on.
 
diff --git a/src/internal/eth/eip712.ts b/src/internal/eth/eip712.ts
index f985551..2357f9a 100644
--- a/src/internal/eth/eip712.ts
+++ b/src/internal/eth/eip712.ts
@@ -255,13 +255,6 @@ export function encodeValue(
     }
     case DataType.INT: {
       const n = parseIntValue(value);
-      if (typeof value === 'number') {
-        const bytes = bigIntToSignedBytesBE(n);
-        if (bytes.length > 0 && bytes[0] === 0x00) {
-          return bytes.subarray(1);
-        }
-        return bytes;
-      }
       return bigIntToSignedBytesBE(n);
     }
     case DataType.BOOL: {
diff --git a/test/eth-eip712.test.ts b/test/eth-eip712.test.ts
index 8057283..7eca418 100644
--- a/test/eth-eip712.test.ts
+++ b/test/eth-eip712.test.ts
@@ -163,6 +163,21 @@ describe('encodeValue', () => {
     ]);
   });
 
+  it.each([
+    [0, '00'], [1, '01'], [-1, 'ff'],
+    [127, '7f'], [128, '0080'], [129, '0081'],
+    [-127, '81'], [-128, '80'], [-129, 'ff7f'],
+    [255, '00ff'], [256, '0100'], [-255, 'ff01'], [-256, 'ff00'],
+    [32767, '7fff'], [32768, '008000'],
+    [-32768, '8000'], [-32769, 'ff7fff'],
+    [65535, '00ffff'], [65536, '010000'],
+  ] as const)('encodes signed %s consistently across input types', (value, expected) => {
+    const typ = parseType('int64', empty);
+    for (const input of [value, String(value), BigInt(value)]) {
+      expect(Buffer.from(encodeValue(typ, input)).toString('hex')).toBe(expected);
+    }
+  });
+
   it('encodes booleans', () => {
     expect(Array.from(encodeValue(parseType('bool', empty), false))).toEqual([0]);
     expect(Array.from(encodeValue(parseType('bool', empty), true))).toEqual([1]);
diff --git a/test/simulator-eth.test.ts b/test/simulator-eth.test.ts
index 22b99be..2fdcb6b 100644
--- a/test/simulator-eth.test.ts
+++ b/test/simulator-eth.test.ts
@@ -265,6 +265,39 @@ describe.skipIf(!ENABLED).sequential.each(simulatorCases())('simulator eth $name
     expect(bytesToHex(signatureBytes(sig1))).not.toBe(bytesToHex(signatureBytes(sig2)));
   }, 60_000);
 
+  it('ethSignTypedMessage preserves signed integer values', async () => {
+    const msg = {
+      types: {
+        EIP712Domain: [{ name: 'name', type: 'string' }],
+        SignedIntegers: [
+          { name: 'positive', type: 'int16' },
+          { name: 'negative', type: 'int8' },
+          { name: 'zero', type: 'int8' },
+        ],
+      },
+      primaryType: 'SignedIntegers',
+      domain: { name: 'Signed integers' },
+      message: { positive: 128, negative: -128, zero: 0 },
+    };
+    const sig = await paired!.ethSignTypedMessage(1n, ETH_KEYPATH, msg, true);
+    expect(signatureBytes(sig)).toHaveLength(65);
+
+    // Compute the EIP-712 digest independently of the wire encoder. The device
+    // must sign +128, -128 and zero, not reinterpret or reject their sign bytes.
+    const domainHash = keccak_256(concatBytes(
+      keccak_256(utf8ToBytes('EIP712Domain(string name)')),
+      keccak_256(utf8ToBytes('Signed integers')),
+    ));
+    const messageHash = keccak_256(concatBytes(
+      keccak_256(utf8ToBytes('SignedIntegers(int16 positive,int8 negative,int8 zero)')),
+      concatBytes(new Uint8Array(31), new Uint8Array([0x80])),
+      concatBytes(new Uint8Array(31).fill(0xff), new Uint8Array([0x80])),
+      new Uint8Array(32),
+    ));
+    const digest = keccak_256(concatBytes(new Uint8Array([0x19, 0x01]), domainHash, messageHash));
+    expectSignatureFromSimulatorAddress(digest, sig);
+  }, 60_000);
+
   it.skipIf(!atLeast926)('ethSignTypedMessage with anti-klepto disabled is deterministic', async () => {
     const sig1 = await paired!.ethSignTypedMessage(1n, ETH_KEYPATH, EIP712_MSG, false);
     const sig2 = await paired!.ethSignTypedMessage(1n, ETH_KEYPATH, EIP712_MSG, false);