The Ethereum blockchain is in constant evolution, driven by regular upgrades known as hard forks. These updates introduce significant changes to the protocol, often reshaping transaction mechanics, network economics, and smart contract behavior. For a hardware wallet provider like Ledger, staying ahead of these shifts is not optional—it's essential to maintaining trust, security, and full functionality for users.
In 2021, two pivotal upgrades—the Berlin and London hard forks—reshaped Ethereum’s landscape. These events tested Ledger’s infrastructure, prompted strategic shifts in node implementation, and revealed critical limitations in how blockchain data is indexed and displayed. Here’s how Ledger navigated these challenges and emerged with more resilient systems.
Understanding Ethereum Hard Forks
A hard fork occurs when a blockchain’s protocol undergoes changes that are not backward-compatible. This means nodes running outdated software will no longer align with the updated chain, effectively creating a split: one legacy chain and one following the new rules.
For Ethereum users, especially those relying on secure custody solutions like Ledger, being on the correct side of the fork is non-negotiable. If a node fails to adopt the new consensus rules before the fork block, it risks processing invalid transactions and losing sync with the network.
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This makes timely integration of hard fork rules into backend systems a top priority. At Ledger, this involves updating Ethereum node clients well in advance of scheduled forks to ensure seamless continuity for all users.
The 2021 Forks: Berlin and London
Two major upgrades defined Ethereum’s evolution in 2021:
- Berlin Fork – Activated at block 12,244,000 on April 15, 2021
- London Fork – Activated at block 12,965,000 on July 30, 2021
These forks introduced critical improvements:
- Enhanced transaction efficiency through EIPs (Ethereum Improvement Proposals) like EIP-2929 and EIP-2930.
- The landmark EIP-1559, implemented in London, reformed transaction fee mechanics by introducing base fee burning—making ETH partially deflationary under certain conditions.
To support these changes, all Ethereum client implementations—including those used by Ledger—had to be upgraded before activation.
Ethereum Clients: Geth vs OpenEthereum
Ethereum is not a single monolithic system but a protocol implemented by various independent clients. The two most relevant to Ledger’s operations are:
- Go-Ethereum (Geth) – The most widely used Ethereum client, known for its reliability and strict adherence to specifications.
- OpenEthereum – A performance-focused client offering advanced features like detailed transaction tracing via
trace_transactionandtrace_blockRPC methods.
Prior to 2021, Ledger relied heavily on OpenEthereum because of its powerful indexing capabilities. It allowed Ledger to reconstruct complex transaction paths—including internal calls between smart contracts—giving users a complete view of their fund movements.
However, this dependence became a vulnerability during the Berlin fork.
Crisis During the Berlin Fork
When the Berlin fork went live, OpenEthereum failed to process new blocks correctly. The development team had shifted focus to a new project (Erigon), leaving critical updates lagging. As a result, nodes using OpenEthereum stopped syncing—putting wallets relying on them at risk.
For Ledger, this was an emergency. Many backend services were tied to OpenEthereum, and disruption meant users couldn't see accurate balances or confirm transactions.
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The response was swift:
- Within days, a patch was released.
- Ledger engineers quickly integrated the fix.
- Operations resumed—making Ledger one of the first major crypto platforms to recover.
This incident served as a wake-up call: overreliance on a single client posed unacceptable risks.
Migration to Go-Ethereum and Indexing Challenges
Post-Berlin, Ledger made a strategic pivot: migrate core infrastructure from OpenEthereum to Geth, the more stable and actively maintained client.
But Geth came with trade-offs:
- No native support for retrieving internal transactions via standard RPC calls.
- To reconstruct contract call trees, Ledger had to use
debug_traceTransaction, which requires replaying every transaction through a local Ethereum Virtual Machine (EVM).
While effective, this method is resource-intensive:
- Indexing speed dropped to 8–10 blocks per second when traces were required.
- Without traces, speeds reached 40–50 blocks per second.
This bottleneck threatened Ledger’s ability to deliver real-time, accurate transaction histories—especially as demand for NFT tracking grew.
Supporting NFTs: The Re-Indexing Challenge
NFTs (Non-Fungible Tokens) operate through smart contracts like ERC-721 and ERC-1155. Tracking ownership requires listening to transfer events, many of which occur deep within nested contract interactions—precisely the kind of internal activity invisible through standard APIs.
To offer full NFT support, Ledger undertook a massive re-indexing of the entire Ethereum blockchain. This meant:
- Replaying historical transactions locally.
- Extracting hidden transfer events from contract executions.
- Building comprehensive indices of user holdings across time.
But performance suffered due to inefficiencies in Geth’s JavaScript-based tracer engine used by debug_traceTransaction.
Optimizing Transaction Tracing
Ledger explored multiple solutions:
- Customizing tracer scripts to extract only necessary data.
- Investigating direct modifications to the Geth codebase.
Then came Geth v1.16, which featured a complete rewrite of the tracer in Go—natively faster and more efficient. After upgrading:
- Tracing performance improved significantly.
- Though still not matching OpenEthereum’s raw speed, it provided a stable foundation for scalable indexing.
This upgrade was pivotal in enabling reliable NFT tracking and historical balance reconstruction.
Core Keywords Integration
Throughout this journey, several core keywords have shaped Ledger’s approach:
- Ethereum hard forks
- Blockchain upgrades
- Node implementation
- Transaction tracing
- Smart contract interactions
- Internal transactions
- EVM replay
- NFT support
These terms reflect both technical depth and user needs—ensuring content aligns with search intent while remaining accessible.
Frequently Asked Questions
What is a hard fork in Ethereum?
A hard fork is a permanent change to the Ethereum protocol that makes previously invalid blocks or transactions valid (or vice versa). Nodes must upgrade their software to remain compatible with the network post-fork.
Why did Ledger switch from OpenEthereum to Geth?
OpenEthereum failed to support the Berlin fork properly and lacked ongoing maintenance. Geth offered greater stability, active development, and broader community support—critical for long-term reliability.
How does Ledger track internal transactions?
Ledger uses debug_traceTransaction in Geth to replay transactions on a local EVM instance, extracting internal calls and contract interactions that aren't visible through standard APIs.
Can I see NFT transfers in my Ledger wallet?
Yes. After re-indexing the Ethereum chain with full tracing enabled, Ledger now supports comprehensive NFT tracking, including past transfers via ERC-721 and ERC-1155 contracts.
Does Ledger support EIP-1559 transactions?
Absolutely. Since the London fork, Ledger has fully supported EIP-1559, allowing users to send transactions with base fee burning and priority fees seamlessly.
Will Ledger handle future Ethereum upgrades?
Yes. Based on lessons from Berlin and London, Ledger maintains proactive monitoring of upcoming EIPs and coordinates node upgrades ahead of scheduled forks to ensure uninterrupted service.
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Delivering Best-in-Class Service
At its core, Ledger’s mission is clear: provide secure, transparent, and future-ready tools for managing digital assets. Hard forks are inevitable—and increasingly complex. But they also represent opportunities to improve resilience, deepen user insight, and expand functionality.
By migrating to robust node clients, optimizing EVM-level tracing, and investing in full-chain re-indexing, Ledger ensures users always have accurate visibility into their crypto activity—whether it’s ETH transfers, DeFi interactions, or NFT ownership.
As Ethereum continues evolving—with upgrades like Proto-Danksharding and Verkle Trees on the horizon—Ledger remains committed to staying one step ahead. Because when the chain changes, your wallet should keep pace without missing a beat.