Firmware updates are software releases installed on EV chargers to improve functionality, fix bugs, enhance compatibility, and address cybersecurity vulnerabilities. Updates can be applied locally during service visits or remotely via over-the-air (OTA) mechanisms through a CPMS or secure update service. Properly managed firmware updates are critical for uptime, safety behavior, interoperability, and long-term fleet reliability.
What Are Firmware Updates?
Firmware controls how a charger operates, including safety functions, charging logic, communications, and diagnostics. Firmware updates may include:
– Security patches and vulnerability fixes
– Stability improvements and bug fixes
– Protocol and backend compatibility improvements (e.g., OCPP behavior)
– Performance tuning (boot time, reconnection logic, thermal derating curves)
– New features (reporting fields, diagnostics, load management enhancements)
– Support for new hardware revisions or accessories
Firmware updates should always be treated as controlled changes to critical infrastructure.
Why Firmware Updates Matter for EV Charging
– Protect the charger fleet from cybersecurity threats and known vulnerabilities
– Improve session success rate and reduce failed starts/stop errors
– Maintain compatibility with CPMS, roaming partners, and payment systems
– Fix reliability issues that cause downtime and support tickets
– Improve thermal performance and extend component lifetime
– Enable consistent behavior across a multi-site rollout (reduce version fragmentation)
Common Firmware Update Methods
Over-the-Air (OTA) Updates
OTA updates are pushed remotely via secure connections.
– Initiated through CPMS or an OEM update platform
– Can be staged by site, charger group, or hardware revision
– Allows monitoring of success rates and automatic retry/rollback
– Minimizes field visits and speeds up security patch deployment
Local / Manual Updates
Local updates are performed on site by technicians.
– Used when chargers have limited connectivity or strict IT restrictions
– Often done via service laptop, USB, or local maintenance interface (implementation-dependent)
– Useful for recovery when OTA updates fail or devices are offline
– Requires stronger process control to avoid inconsistent versions across sites
What a Safe Firmware Update Process Includes
Planning and Validation
– Release notes and versioning rules (what changed and why)
– Compatibility check (charger model, hardware revision, market requirements)
– Regression testing, including safety behavior and fault handling
– Cybersecurity checks, including dependency and vulnerability review
Secure Delivery and Installation
– Firmware signing to ensure authenticity
– Firmware integrity validation on the charger before install/boot
– Encrypted transport (TLS) between charger and update service
– Authorization controls: who can trigger updates, when, and to which devices
Rollout Control
– Pilot rollout (small group) before wide deployment
– Maintenance windows to reduce user disruption
– Staged deployment with go/no-go gates
– Rollback plan to last-known-good firmware if issues appear
Post-Update Monitoring
– Confirm charger returns to “Available” state and remains stable
– Monitor session success rate, fault rate, reconnect behavior, and uptime
– Verify metering and transaction records remain correct
– Capture update logs, timestamps, and device response details for auditability
Risks and Failure Modes
– Power loss mid-update without a safe recovery mechanism
– Connectivity drops or firewall restrictions interrupting downloads
– Version fragmentation across a fleet due to partial rollout completion
– Regressions that increase failed sessions or nuisance faults
– Misconfigured update targets (wrong model/hardware revision)
– Key/certificate issues that block secure communications after update
– In markets with strict metering/payment rules, updates may require additional validation to avoid compliance disruption
Best Practices
– Maintain a controlled firmware lifecycle management process with staged releases
– Use secure boot and signed firmware where supported
– Keep a “last known good” image and safe rollback capability
– Automate reporting: which chargers run which version, and update success status
– Coordinate updates with operations (support readiness, maintenance coverage)
– Ensure DNS/NTP connectivity for reliable logs and time-based reporting
– Document update events for tenders and audits (who/when/what/where)
Limitations to Consider
– Some sites restrict outbound connectivity, limiting OTA update feasibility
– Legacy hardware may not support robust signing, rollback, or secure boot
– Third-party modules (modems, payment terminals) may need separate update processes
– Updates can impact user experience if applied during high-utilization periods
– Firmware updates do not replace good commissioning; installation issues can still cause faults
Related Glossary Terms
Firmware Lifecycle Management
Firmware Signing
Firmware Integrity Validation
Secure Update Pipeline
Secure Boot
Charger Diagnostics
Charging Uptime
Field Provisioning