I upgraded a chain that uses Grandpa/Aura with code for instant seal by mistake. I believe it may be possible to revert some blocks:


But cannot find any documentation on how to do this. It is also asked here: How to unbrick a Substrate Chain? --revert?

But no answer for how to use --revert is given.

2 Answers 2


You can use the revert command to revert unfinalized blocks. If you need to revert finalized blocks then I suggest you do the following:

  • Assuming you want to revert to block #42;
  • Add the hash of block #43 to the chain spec under badBlocks (example: https://raw.githubusercontent.com/paritytech/polkadot/a4931d93388688af2e39e1aca77a6dcefd4bbd10/node/service/chain-specs/kusama.json);
  • Sync a node from scratch and it should stop importing blocks after #42 (since #43 is blacklisted it will fail to import);
  • You can now deploy this database to other validators and they should start authoring (and finalizing on top of #42). Alternatively you can also just resync using the new chain spec;
  • Since you are reverting finality all clients on the network will need to resync (using the new chainspec with badBlocks populated).
  • If this answered your question you should consider accepting the response :)
    – André
    Commented Mar 18, 2022 at 16:52

I figured out how to revert some blocks:

./{chain executable} revert --base-path /home/ubuntu/chains --chain {chain name}--keep-blocks 351284 --pruning archive

For options:

./{chain executable} revert --help
  • 1
    Did it work? AFAIK this only reverts un-finalized blocks. Commented Feb 17, 2022 at 18:59

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