I am running a private chain for my own purposes. Rather: it's a "public" discoverable chain but not any known or publicized chain.

I want to continue to run this with PoW and no difficulty bomb. Is this possible? I had though I could do it with one flag in Parity, but this question suggests maybe not?

1 Answer 1


Yes, you can defuse the bomb by adding the defuseBombTransition parameter to the ethash parameters in the chain spec json, like this:

"bombDefuseTransition": "0x539",

The lower the value, the earlier the bomb is disabled. You can see this parameter in action for the expanse network.

  • Thanks for clearing that up. I'll edit my answer to the referenced question to make it correct. :-) Commented May 9, 2017 at 15:52
  • Thanks! What encoding is that number in, and how would I determine what block to de-fuse (makes sense) at? I'm thinking that for a dev/private network, I would just use 0x000 if I'm starting with a Morden or Ropstein genesis file, slightly modified for my own use?
    – stone.212
    Commented May 9, 2017 at 20:10
  • It's hex number, 0x0 should work, but the bomb kicks in very late, so basically an low number should do.
    – q9f
    Commented May 9, 2017 at 20:18

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