Right before the BCH fork a multisig (2 of 3) transaction was signed by the other party, and mine after the fork and successfully broadcasted (coinb.in), so got my BTC.

Later I realized there might be BCH in there as well, but broadcasting the same final raw hex on the Bitcoin Cash mainnet (viabtc.com) keeps failing.

Am I missing something here? Or is it impossible because the other party's raw transaction hex code is not recognized on the BCH chain?

Broadcasting on blockdozer returns; An error occured: 16: mandatory-script-verify-flag-failed (Signature must use SIGHASH_FORKID). Code:-26

  • Was the multisig transaction confirmed before or after the fork block? If before, you should simply be able to spend it on the BCH chain. If after, both parties will have to re-sign with BCH rules, as in the answer below. It would help if you can share the txid. Jan 26, 2018 at 0:32

1 Answer 1


You cannot simply rebroadcast a bitcoin transaction on the bcash chain, due to replay protection. You need to sign the transaction using the SIGHASH_FORKID as the error message says, which means you will need to use a BCH wallet to resign the transaction


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