Espressif Systems has just published a bug advisory for ESP32-C5 chips that identifies and fixes three bugs related to PSRAM and sleep coexistence stability.
New microcontrollers often have issues when they are first released, leading companies to issue errata listing bugs and potential fixes, as we’ve previously seen with the Raspberry Pi RP2350 A4 stepping, which fixes the E9 GPIO Erratum with a new revision of the silicon.
Espressif identified three issues with the ESP32-C5:
- PSRAM Reset Hang – When ESP32-C5 series chips run ESP-IDF v5.5.1 with PSRAM enabled, CPU or digital reset operations may hang. This triggers a secondary RTC WDT reset. If the rollback feature (CONFIG_BOOTLOADER_APP_ROLLBACK_ENABLE, disabled by default) is enabled, this sequence may result in an OTA rollback.
- AES and SHA Access to PSRAM – When ESP32-C5 chips run ESP-IDF v5.5.1, PSRAM data may be corrupted when AES or SHA hardware accesses buffers that are not aligned to a 16-byte boundary.
- Sleep Coexistence Stability – When ESP32-C5 series chips run ESP-IDF v5.5.1 with ESP_WIFI_ENHANCED_LIGHT_SLEEP enabled, task watchdog timeouts may occur during Wi-Fi/BLE/IEEE 802.15.4 dual-mode or tri-mode coexistence, and the system may fail to recover after a CPU reset.
The good news is that all three already have fixes or mitigations in the ESP-IDF framework without requiring a new silicon revision.
If your firmware is based on ESP-IDF v5.5.1, v6.0-beta1, or the master branch, you’d need to upgrade to v5.5.2, v6.0 release, or v6.1 once they are released, or just upgrade to the patched ESP-IDF version listed in the tables in the AR2025-008 advisory.
Here are the links to the ESP-IDF v5.5 commits since I assume that’s what most people are using (stable release): PSRAM Reset Hang (ddb9f5d), AES/SHA access to PSRAM (86bd3d3), and Sleep coexistence stability (e3d0b19). In case you encounter any issues during the upgrade process, provide the ESP-IDF version number or Commit ID, and Espressif says they will confirm and handle it.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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