Secure OTA (over-the-air) updates are a method of remotely updating a device’s firmware or software while ensuring the update package is authentic, unchanged, and installed in a way that prevents tampering, rollback attacks, or device “bricking.” For EV chargers, secure OTA updates are a core part of maintaining cybersecurity and reliability across a deployed fleet.
Why Secure OTA Updates Matter in EV Charging Infrastructure
Public and commercial chargers are long-lived, internet-connected assets. Without secure updates, vulnerabilities can remain exploitable for years.
– Enables fast patching of security vulnerabilities across a charger fleet
– Prevents attackers from pushing malicious firmware that could disrupt charging or steal credentials
– Reduces operational cost by avoiding on-site update visits
– Supports compliance and procurement requirements for EV charging cybersecurity
– Improves uptime by allowing controlled rollout, monitoring, and recovery
Secure OTA updates are especially important when chargers use PKI, OCPP security profiles, or ISO 15118 features that rely on trusted software.
How Secure OTA Updates Work
A secure OTA pipeline protects the update from build to installation.
– Firmware is built in a controlled environment and cryptographically signed
– Charger downloads the update over a protected channel (typically TLS)
– Charger verifies integrity and authenticity (signature verification) before installing
– Update is installed using a safe mechanism (A/B partitions or fallback image)
– Charger reboots and secure boot verifies the new firmware at startup
– Health checks confirm correct operation; otherwise the device rolls back to a known-good version
Strong implementations include rollback protection so attackers cannot downgrade devices to older vulnerable firmware.
Key Security Controls in Secure OTA
Secure OTA is a system, not a single feature.
– Firmware signing (only trusted publishers can release valid updates)
– Secure boot (only signed/verified firmware can run after reboot)
– Hardware root of trust (often a secure element or protected key storage)
– Anti-rollback / version control (prevents downgrade to vulnerable releases)
– Encrypted transport (TLS) and authenticated backend endpoints
– Update integrity checks (hash verification, manifest validation)
– Staged rollout (canary updates, region/site segmentation, pause/rollback controls)
– Audit logs (who released what, when devices updated, success/failure reasons)
Operational Best Practices for Charger Fleets
Secure OTA must be designed for real-world conditions like unstable connectivity and partial site outages.
– Schedule updates during low-usage windows to reduce service disruption
– Require minimum battery/UPS state where applicable for safe flashing
– Use delta updates only if integrity guarantees remain strong
– Maintain a signed recovery image and service procedure for failed updates
– Monitor fleet version compliance and enforce critical security patches
– Separate safety-critical firmware updates from UI/content updates where possible
Key Benefits of Secure OTA Updates
– Faster vulnerability response and reduced cyber risk
– Lower maintenance costs and improved fleet uptime
– More consistent software versions across deployed chargers
– Supports continuous improvement (features, bug fixes, performance tuning)
– Strengthens trust in connected charging services and roaming ecosystems
Limitations to Consider
– Requires robust key management and protected signing infrastructure
– Poor design can increase downtime risk if recovery/rollback is weak
– Legacy hardware may limit secure boot, storage partitions, or crypto performance
– Update governance is critical (approvals, testing, release management)
– Backend compromise risk must be managed (access control, monitoring, incident response)
Related Glossary Terms
OTA updates
Firmware signing
Secure boot
Secure firmware
Firmware lifecycle management
Firmware integrity validation
Secure element
PKI infrastructure
OCPP security profiles
Incident response plan