diff --git a/contracts/core/EntryPoint.sol b/contracts/core/EntryPoint.sol
index ddc44baf6..3f880b795 100644
--- a/contracts/core/EntryPoint.sol
+++ b/contracts/core/EntryPoint.sol
@@ -438,13 +438,8 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
                 }(op, opInfo.userOpHash, missingAccountFunds)
             returns (uint256 _validationData) {
                 validationData = _validationData;
-            } catch Error(string memory revertReason) {
-                revert FailedOp(
-                    opIndex,
-                    string.concat("AA23 reverted: ", revertReason)
-                );
             } catch {
-                revert FailedOp(opIndex, "AA23 reverted (or OOG)");
+                revert FailedOpWithRevert(opIndex, "AA23 reverted", Exec.getReturnData(REVERT_REASON_MAX_LEN));
             }
             if (paymaster == address(0)) {
                 DepositInfo storage senderInfo = deposits[sender];
@@ -503,13 +498,8 @@ contract EntryPoint is IEntryPoint, StakeManager, NonceManager, ReentrancyGuard,
             returns (bytes memory _context, uint256 _validationData) {
                 context = _context;
                 validationData = _validationData;
-            } catch Error(string memory revertReason) {
-                revert FailedOp(
-                    opIndex,
-                    string.concat("AA33 reverted: ", revertReason)
-                );
             } catch {
-                revert FailedOp(opIndex, "AA33 reverted (or OOG)");
+                revert FailedOpWithRevert(opIndex, "AA33 reverted", Exec.getReturnData(REVERT_REASON_MAX_LEN));
             }
         }
     }
diff --git a/contracts/interfaces/IEntryPoint.sol b/contracts/interfaces/IEntryPoint.sol
index 2bde4c1df..2b48ce7e8 100644
--- a/contracts/interfaces/IEntryPoint.sol
+++ b/contracts/interfaces/IEntryPoint.sol
@@ -102,6 +102,15 @@ interface IEntryPoint is IStakeManager, INonceManager {
      */
     error FailedOp(uint256 opIndex, string reason);
 
+    /**
+     * A custom revert error of handleOps, to report a revert by account or paymaster.
+     * @param opIndex - Index into the array of ops to the failed one (in simulateValidation, this is always zero).
+     * @param reason  - Revert reason. see FailedOp(uint,string), above
+     * @param inner   - data from inner cought revert reason
+     * @dev note that inner is truncated to 2048 bytes
+     */
+    error FailedOpWithRevert(uint256 opIndex, string reason, bytes inner);
+
     error PostOpReverted(bytes returnData);
 
     /**
diff --git a/contracts/samples/TokenPaymaster.sol b/contracts/samples/TokenPaymaster.sol
index 632f1e374..48c085597 100644
--- a/contracts/samples/TokenPaymaster.sol
+++ b/contracts/samples/TokenPaymaster.sol
@@ -42,8 +42,6 @@ contract TokenPaymaster is BasePaymaster, UniswapHelper, OracleHelper {
 
     event UserOperationSponsored(address indexed user, uint256 actualTokenCharge, uint256 actualGasCost, uint256 actualTokenPrice);
 
-    event PostOpReverted(address indexed user, uint256 preCharge);
-
     event Received(address indexed sender, uint256 value);
 
     /// @notice All 'price' variables are multiplied by this value to avoid rounding up
diff --git a/reports/gas-checker.txt b/reports/gas-checker.txt
index 9249f5389..0be941e8a 100644
--- a/reports/gas-checker.txt
+++ b/reports/gas-checker.txt
@@ -4,7 +4,7 @@
 ╔══════════════════════════╤════════╗
 ║ gas estimate "simple"    │  29002 ║
 ╟──────────────────────────┼────────╢
-║ gas estimate "big tx 5k" │ 125260 ║
+║ gas estimate "big tx 5k" │ 125248 ║
 ╚══════════════════════════╧════════╝
 
 ╔════════════════════════════════╤═══════╤═══════════════╤════════════════╤═════════════════════╗
@@ -12,28 +12,28 @@
 ║                                │       │               │     (delta for │        (compared to ║
 ║                                │       │               │    one UserOp) │     account.exec()) ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ simple                         │     1 │         81934 │                │                     ║
+║ simple                         │     1 │         81930 │                │                     ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ simple - diff from previous    │     2 │               │          44191 │               15189 ║
+║ simple - diff from previous    │     2 │               │          44187 │               15185 ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ simple                         │    10 │        479794 │                │                     ║
+║ simple                         │    10 │        479718 │                │                     ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ simple - diff from previous    │    11 │               │          44203 │               15201 ║
+║ simple - diff from previous    │    11 │               │          44223 │               15221 ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ simple paymaster               │     1 │         88232 │                │                     ║
+║ simple paymaster               │     1 │         88187 │                │                     ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ simple paymaster with diff     │     2 │               │          43183 │               14181 ║
+║ simple paymaster with diff     │     2 │               │          43126 │               14124 ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ simple paymaster               │    10 │        477132 │                │                     ║
+║ simple paymaster               │    10 │        476670 │                │                     ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ simple paymaster with diff     │    11 │               │          43254 │               14252 ║
+║ simple paymaster with diff     │    11 │               │          43173 │               14171 ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ big tx 5k                      │     1 │        182991 │                │                     ║
+║ big tx 5k                      │     1 │        182963 │                │                     ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ big tx - diff from previous    │     2 │               │         144702 │               19442 ║
+║ big tx - diff from previous    │     2 │               │         144686 │               19438 ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ big tx 5k                      │    10 │       1485426 │                │                     ║
+║ big tx 5k                      │    10 │       1485374 │                │                     ║
 ╟────────────────────────────────┼───────┼───────────────┼────────────────┼─────────────────────╢
-║ big tx - diff from previous    │    11 │               │         144739 │               19479 ║
+║ big tx - diff from previous    │    11 │               │         144759 │               19511 ║
 ╚════════════════════════════════╧═══════╧═══════════════╧════════════════╧═════════════════════╝
 
diff --git a/test/entrypoint.test.ts b/test/entrypoint.test.ts
index 24a0bd878..dc235517d 100644
--- a/test/entrypoint.test.ts
+++ b/test/entrypoint.test.ts
@@ -286,7 +286,7 @@ describe('EntryPoint', function () {
         // if we get here, it means the userOp passed first sim and reverted second
         expect.fail(null, null, 'should fail on first simulation')
       } catch (e: any) {
-        expect(e.message).to.include('Revert after first validation')
+        expect(decodeRevertReason(e)).to.include('Revert after first validation')
       }
     })
 
@@ -334,7 +334,7 @@ describe('EntryPoint', function () {
             const tx = await entryPoint.handleOps([badOp], beneficiaryAddress, { gasLimit: 1e6 })
             await tx.wait()
           } else {
-            expect(e.message).to.include('AA23 reverted (or OOG)')
+            expect(decodeRevertReason(e)).to.include('AA23 reverted')
           }
         }
       })
@@ -359,7 +359,7 @@ describe('EntryPoint', function () {
             const tx = await entryPoint.handleOps([badOp], beneficiaryAddress, { gasLimit: 1e6 })
             await tx.wait()
           } else {
-            expect(e.message).to.include('AA23 reverted (or OOG)')
+            expect(decodeRevertReason(e)).to.include('AA23 reverted')
           }
         }
       })
@@ -726,7 +726,7 @@ describe('EntryPoint', function () {
           verificationGasLimit: 10000
         }, accountOwner, entryPoint)
         await expect(simulateValidation(op1, entryPoint.address))
-          .to.revertedWith('AA23 reverted (or OOG)')
+          .to.revertedWith('AA23 reverted')
       })
     })
 
diff --git a/test/entrypointsimulations.test.ts b/test/entrypointsimulations.test.ts
index 8920057ab..2ef719d73 100644
--- a/test/entrypointsimulations.test.ts
+++ b/test/entrypointsimulations.test.ts
@@ -142,7 +142,7 @@ describe('EntryPointSimulations', function () {
     it('should revert on oog if not enough verificationGas', async () => {
       const op = await fillAndSign({ sender: account.address, verificationGasLimit: 1000 }, accountOwner, entryPoint)
       await expect(simulateValidation(op, entryPoint.address)).to
-        .revertedWith('AA23 reverted (or OOG)')
+        .revertedWith('AA23 reverted')
     })
 
     it('should succeed if validateUserOp succeeds', async () => {
diff --git a/test/gnosis.test.ts b/test/gnosis.test.ts
index 24819edf0..b763e1abb 100644
--- a/test/gnosis.test.ts
+++ b/test/gnosis.test.ts
@@ -23,7 +23,7 @@ import {
   deployEntryPoint,
   getBalance,
   HashZero,
-  isDeployed
+  isDeployed, decodeRevertReason
 } from './testutils'
 import { fillAndSign } from './UserOp'
 import { defaultAbiCoder, hexConcat, hexZeroPad, parseEther } from 'ethers/lib/utils'
@@ -107,7 +107,10 @@ describe('Gnosis Proxy', function () {
 
     const anotherEntryPoint = await new EntryPoint__factory(ethersSigner).deploy()
 
-    await expect(anotherEntryPoint.handleOps([op], beneficiary)).to.revertedWith('account: not from entrypoint')
+    // await expect(
+    expect(await anotherEntryPoint.handleOps([op], beneficiary)
+      .catch(e => decodeRevertReason(e)))
+      .to.include('account: not from entrypoint')
   })
 
   it('should fail on invalid userop', async function () {
diff --git a/test/paymaster.test.ts b/test/paymaster.test.ts
index 5fcb410e6..d58063974 100644
--- a/test/paymaster.test.ts
+++ b/test/paymaster.test.ts
@@ -22,7 +22,7 @@ import {
   createAddress,
   ONE_ETH,
   createAccount,
-  getAccountAddress
+  getAccountAddress, decodeRevertReason
 } from './testutils'
 import { fillAndSign, simulateValidation } from './UserOp'
 import { hexConcat, parseEther } from 'ethers/lib/utils'
@@ -100,12 +100,14 @@ describe('EntryPoint with paymaster', function () {
           paymasterAndData: paymaster.address,
           callData: calldata
         }, accountOwner, entryPoint)
-        await expect(entryPoint.callStatic.handleOps([op], beneficiaryAddress, {
+        expect(await entryPoint.callStatic.handleOps([op], beneficiaryAddress, {
           gasLimit: 1e7
-        })).to.revertedWith('AA33 reverted: TokenPaymaster: no balance')
-        await expect(entryPoint.handleOps([op], beneficiaryAddress, {
+        }).catch(e => decodeRevertReason(e)))
+          .to.include('TokenPaymaster: no balance')
+        expect(await entryPoint.handleOps([op], beneficiaryAddress, {
           gasLimit: 1e7
-        })).to.revertedWith('AA33 reverted: TokenPaymaster: no balance')
+        }).catch(e => decodeRevertReason(e)))
+          .to.include('TokenPaymaster: no balance')
       })
     })
 
@@ -120,9 +122,10 @@ describe('EntryPoint with paymaster', function () {
           verificationGasLimit: 1e7,
           paymasterAndData: paymaster.address
         }, accountOwner, entryPoint)
-        await expect(entryPoint.callStatic.handleOps([op], beneficiaryAddress, {
+        expect(await entryPoint.callStatic.handleOps([op], beneficiaryAddress, {
           gasLimit: 1e7
-        }).catch(rethrow())).to.revertedWith('TokenPaymaster: no balance')
+        }).catch(e => decodeRevertReason(e)))
+          .to.include('TokenPaymaster: no balance')
       })
 
       it('should succeed to create account with tokens', async () => {
diff --git a/test/samples/TokenPaymaster.test.ts b/test/samples/TokenPaymaster.test.ts
index 4a1e94117..007528882 100644
--- a/test/samples/TokenPaymaster.test.ts
+++ b/test/samples/TokenPaymaster.test.ts
@@ -49,6 +49,11 @@ function generatePaymasterAndData (pm: string, tokenPrice?: BigNumberish): strin
 
 const priceDenominator = BigNumber.from(10).pow(26)
 
+function uniq (arr: any[]): any[] {
+  // remove items with duplicate "name" attribute
+  return Object.values(arr.reduce((set, item) => ({ ...set, [item.name]: item }), {}))
+}
+
 describe('TokenPaymaster', function () {
   const minEntryPointBalance = 1e17.toString()
   const initialPriceToken = 100000000 // USD per TOK
@@ -56,12 +61,12 @@ describe('TokenPaymaster', function () {
   const ethersSigner = ethers.provider.getSigner()
   const beneficiaryAddress = '0x'.padEnd(42, '1')
   const testInterface = new Interface(
-    [
+    uniq([
       ...TestUniswap__factory.abi,
       ...TestERC20__factory.abi,
       ...TokenPaymaster__factory.abi,
       ...EntryPoint__factory.abi
-    ]
+    ])
   )
 
   let chainId: number
@@ -148,15 +153,17 @@ describe('TokenPaymaster', function () {
       callData
     }, entryPoint)
     op = signUserOp(op, accountOwner, entryPoint.address, chainId)
-    await expect(
-      entryPoint.handleOps([op], beneficiaryAddress, { gasLimit: 1e7 })
-    ).to.be.revertedWith('AA33 reverted: ERC20: insufficient allowance')
+    // await expect(
+    expect(await entryPoint.handleOps([op], beneficiaryAddress, { gasLimit: 1e7 })
+      .catch(e => decodeRevertReason(e)))
+      .to.include('ERC20: insufficient allowance')
 
     await token.sudoApprove(account.address, paymaster.address, ethers.constants.MaxUint256)
 
-    await expect(
-      entryPoint.handleOps([op], beneficiaryAddress, { gasLimit: 1e7 })
-    ).to.revertedWith('AA33 reverted: ERC20: transfer amount exceeds balance')
+    expect(await entryPoint.handleOps([op], beneficiaryAddress, { gasLimit: 1e7 })
+      .catch(e => decodeRevertReason(e)))
+      .to.include('ERC20: transfer amount exceeds balance')
+
     await ethers.provider.send('evm_revert', [snapshot])
   })
 
diff --git a/test/testutils.ts b/test/testutils.ts
index 8307ce9af..d8c79a416 100644
--- a/test/testutils.ts
+++ b/test/testutils.ts
@@ -1,7 +1,7 @@
 import { ethers } from 'hardhat'
 import {
   arrayify,
-  hexConcat,
+  hexConcat, Interface,
   keccak256,
   parseEther
 } from 'ethers/lib/utils'
@@ -15,7 +15,7 @@ import {
   SimpleAccountFactory__factory,
   SimpleAccount__factory,
   SimpleAccountFactory,
-  TestAggregatedAccountFactory
+  TestAggregatedAccountFactory, TestPaymasterRevertCustomError__factory
 } from '../typechain'
 import { BytesLike } from '@ethersproject/bytes'
 import { expect } from 'chai'
@@ -157,7 +157,18 @@ export function rethrow (): (e: Error) => void {
   }
 }
 
-export function decodeRevertReason (data: string, nullIfNoMatch = true): string | null {
+const decodeRevertReasonContracts = new Interface([
+  ...[
+    ...EntryPoint__factory.createInterface().fragments,
+    ...TestPaymasterRevertCustomError__factory.createInterface().fragments
+  ].filter(f => f.type === 'error')
+]) //
+
+export function decodeRevertReason (data: string | Error, nullIfNoMatch = true): string | null {
+  if (typeof data !== 'string') {
+    const err = data as any
+    data = (err.data ?? err.error.data) as string
+  }
   const methodSig = data.slice(0, 10)
   const dataParams = '0x' + data.slice(10)
 
@@ -165,25 +176,31 @@ export function decodeRevertReason (data: string, nullIfNoMatch = true): string
     const [err] = ethers.utils.defaultAbiCoder.decode(['string'], dataParams)
     // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
     return `Error(${err})`
-  } else if (methodSig === '0x00fa072b') {
-    const [opindex, paymaster, msg] = ethers.utils.defaultAbiCoder.decode(['uint256', 'address', 'string'], dataParams)
-    // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
-    return `FailedOp(${opindex}, ${paymaster !== AddressZero ? paymaster : 'none'}, ${msg})`
   } else if (methodSig === '0x4e487b71') {
     const [code] = ethers.utils.defaultAbiCoder.decode(['uint256'], dataParams)
     return `Panic(${panicCodes[code] ?? code} + ')`
-  } else if (methodSig === '0x8d6ea8be') {
-    const [reason] = ethers.utils.defaultAbiCoder.decode(['string'], dataParams)
-    return `CustomError("${reason as string}")`
-  } else if (methodSig === '0xad7954bc') {
-    const [reasonBytes] = ethers.utils.defaultAbiCoder.decode(['bytes'], dataParams)
-    const reason = decodeRevertReason(reasonBytes)
-    return `PostOpReverted(${reason as string})`
   }
-  if (!nullIfNoMatch) {
-    return data
+
+  try {
+    const err = decodeRevertReasonContracts.parseError(data)
+    // let args: any[] = err.args as any
+
+    // treat any error "bytes" argument as possible error to decode (e.g. FailedOpWithRevert, PostOpReverted)
+    const args = err.args.map((arg: any, index) => {
+      switch (err.errorFragment.inputs[index].type) {
+        case 'bytes' : return decodeRevertReason(arg)
+        case 'string': return `"${(arg as string)}"`
+        default: return arg
+      }
+    })
+    return `${err.name}(${args.join(',')})`
+  } catch (e) {
+    // throw new Error('unsupported errorSig ' + data)
+    if (!nullIfNoMatch) {
+      return data
+    }
+    return null
   }
-  return null
 }
 
 let currentNode: string = ''
@@ -215,12 +232,14 @@ export async function checkForGeth (): Promise<void> {
 // becomes:
 // { first: "a", second: "20" }
 export function objdump (obj: { [key: string]: any }): any {
-  return Object.keys(obj)
-    .filter(key => key.match(/^[\d_]/) == null)
-    .reduce((set, key) => ({
-      ...set,
-      [key]: decodeRevertReason(obj[key].toString(), false)
-    }), {})
+  return obj == null
+    ? null
+    : Object.keys(obj)
+      .filter(key => key.match(/^[\d_]/) == null)
+      .reduce((set, key) => ({
+        ...set,
+        [key]: decodeRevertReason(obj[key].toString(), false)
+      }), {})
 }
 
 export async function checkForBannedOps (txHash: string, checkPaymaster: boolean): Promise<void> {
diff --git a/test/verifying_paymaster.test.ts b/test/verifying_paymaster.test.ts
index 5103f2cb6..6c8ee7294 100644
--- a/test/verifying_paymaster.test.ts
+++ b/test/verifying_paymaster.test.ts
@@ -9,7 +9,7 @@ import {
 } from '../typechain'
 import {
   createAccount,
-  createAccountOwner, createAddress,
+  createAccountOwner, createAddress, decodeRevertReason,
   deployEntryPoint
 } from './testutils'
 import { fillAndSign, simulateValidation } from './UserOp'
@@ -58,7 +58,9 @@ describe('EntryPoint with VerifyingPaymaster', function () {
         sender: account.address,
         paymasterAndData: hexConcat([paymaster.address, defaultAbiCoder.encode(['uint48', 'uint48'], [MOCK_VALID_UNTIL, MOCK_VALID_AFTER]), '0x1234'])
       }, accountOwner, entryPoint)
-      await expect(simulateValidation(userOp, entryPoint.address)).to.be.revertedWith('invalid signature length in paymasterAndData')
+      expect(await simulateValidation(userOp, entryPoint.address)
+        .catch(e => decodeRevertReason(e)))
+        .to.include('invalid signature length in paymasterAndData')
     })
 
     it('should reject on invalid signature', async () => {
@@ -66,7 +68,9 @@ describe('EntryPoint with VerifyingPaymaster', function () {
         sender: account.address,
         paymasterAndData: hexConcat([paymaster.address, defaultAbiCoder.encode(['uint48', 'uint48'], [MOCK_VALID_UNTIL, MOCK_VALID_AFTER]), '0x' + '00'.repeat(65)])
       }, accountOwner, entryPoint)
-      await expect(simulateValidation(userOp, entryPoint.address)).to.be.revertedWith('ECDSA: invalid signature')
+      expect(await simulateValidation(userOp, entryPoint.address)
+        .catch(e => decodeRevertReason(e)))
+        .to.include('ECDSA: invalid signature')
     })
 
     describe('with wrong signature', () => {