Ethereum’s Istanbul Hark Fork

Kaven Choi
Etherscan Blog
Published in
2 min readDec 10, 2019


Announced on, the upgrade on Ethereum in the form of a Hard Fork is scheduled at block number #9,069,000. When the Ethereum developers introduce any improvements, the blockchain would need to branch out also called “forking” to a forked chain that implements all the changes introduced. Agreeing users will support the new fork and the old fork will be obsolete.

On Etherscan, Istanbul Hark Fork is successful.

Below are the EIPs introduced:

EIP-152: Add Blake2 compression function F precompile

  • EIP-152 will enable the BLAKE2b hash function and other higher-round 64-bit BLAKE2 variants to run cheaply on the EVM, allowing easier interoperability between Ethereum and Zcash as well as other Equihash-based PoW coins.

EIP-1108: Reduce alt_bn128 precompile gas costs

  • EIP-1108 involves re-pricing the precompiles gas costs benefiting a number of privacy solutions and scaling solutions on Ethereum.

EIP-1344: Add ChainID opcode

  • EIP-1344 adds an opcode that returns the current chain’s EIP-155 unique identifier.

EIP-1884: Repricing for trie-size-dependent opcodes

  • EIP-1884 proposes repricing certain opcodes, to obtain a good balance between gas expenditure and resource consumption.

EIP-2028: Calldata gas cost reduction

  • EIP2028 propose to reduce the gas cost of Calldata (GTXDATANONZERO) from its current value of 68 gas per byte to 16 gas per byte, to be backed by mathematical modeling and empirical estimates. Allows more layer 2 data to fit in a single block

EIP-2200: Rebalance net-metered SSTORE gas cost with consideration of SLOAD gas cost change

  • EIP-2200 implements and provides a structured definition of net gas metering changes for SSTORE opcode, enabling new usages for contract storage, and reducing excessive gas costs where it doesn’t match how most implementation works.