I've been trying to fork the cryptocurrency Clams for about a week now. All of my code is correct to the coin's specifications, but I've been stuck on the creation of the blockchain. The developers have removed the code involving the genesis block and there doesn't seem to be any way for me to generate the PoS genesis block. If anyone has any experience with PoS coins, I would appreciate any advice incredibly. Thank you.

  • How do you know all of your code is correct? Commented Aug 19, 2015 at 6:40
  • What would it mean to have a valid PoS genesis block? What would you even be proving stake of?
    – Nick ODell
    Commented Aug 19, 2015 at 8:31

3 Answers 3


Quick and dirty solution? Use their own initial hash.

  • Will this mean that the client might accidentally download the other blockchain? Commented Dec 11, 2015 at 1:55

how to To create a genesis block


Delete Both Main Merkle & Genesis Merkle (example)
Main genesis block

static const uint256 hashGenesisBlock("0x000004611c87517dfd29fe7f34bd6da2e1ad3d305ac12afe80a3229069390f68");


static const uint256 hashGenesisBlock("");

and inside Main.h too
Testnet Genesis

static const uint256 hashGenesisBlockTestNet("0x000004611c87517dfd29fe7f34bd6da2e1ad3d305ac12afe80a3229069390f68");


static const uint256 hashGenesisBlockTestNet("");

inside Main.cpp Change this to your Timestamp wanted

const char* pszTimestamp = "Blockchain.info Block #312427 2014-07-25 14:15:16";

inside: Main.cpp
Change these both to your Epoch Time wanted //Unixtime check google

txNew.nTime = 1406297716;  (example) (example) 
block.nTime    = 1406297716;  (example) (example) (example)

inside: Main.cpp Change these to 0

block.nNonce   = !fTestNet ? 190271 : 190271;   (example) (example) (example)

inside: Main.cpp Change this to say true

if (false && (block.GetHash() != hashGenesisBlock))


if (true && (block.GetHash() != hashGenesisBlock))

inside: Main.cpp Delete the Merkle root

assert(block.hashMerkleRoot == uint256("0xc9c8f6250a60dc79038b9ae68ff747488ac80d4a2db0b194cf49628495448d21"));


assert(block.hashMerkleRoot == uint256(""));

Now Compile the Wallet, and let it crash. as next you find on the debug file the Merkle Root/Hash replace it into the blank space from you step before. but make sure that you have to add to the beginning 0x just compare and undo the steps with the new infos.

Save the Main.cpp with the New hashMerkleRoot added by you. and recompile. then start again and let the wallet crash one more time like before. visit again the debug log and replace other infos.

you find in the debug block.nNonce you remind that you remove that before. and the Genesis/Block Hash .. you remind you delete this as first. copy and paste into the free space inside the Main.h and add 0x on the beginning too.

That's it. Save all files and compile one more time. and you are a Coin Developer :-)

  • I have followed this example and got stuck with the following error -> ERROR: CTxDB::LoadBlockIndex() : Failed stake modifier checkpoint height=0 <- described in details in a separate question -> bitcoin.stackexchange.com/questions/61384/… - appreciate your help.
    – m1k3y3
    Commented Oct 27, 2017 at 15:22

You can get original blockchain (curracy that you fork) and read genesis block. Then you can see what happens there and maybe you will find bug in the code faster.

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