no need to tostring hash
MODIFY
WalletWasabi/Extensions/RPCClientExtensions.cs
WalletWasabi/Extensions/RPCClientExtensions.cs
@@ -24,7 +24,7 @@ namespace NBitcoin.RPC
/// <returns>Returns the current block on timeout or exit</returns>
public static async Task<(Height height, uint256 hash)> WaitForBlockAsync(this RPCClient rpc, uint256 blockhash, long timeout = 0)
{
- var resp = await rpc.SendCommandAsync("waitforblock", blockhash.ToString(), timeout);
+ var resp = await rpc.SendCommandAsync("waitforblock", blockhash, timeout);
return (int.Parse(resp.Result["height"].ToString()), uint256.Parse(resp.Result["hash"].ToString()));
}

no need to tostring hash