1/3 Bug Advisory Title Bug Advisory for System Stability Issues When Using PSRAM on ESP32-C5 and ESP32-C61 Issue Date 2026/05/06 Advisory Number AR2026-002 Serial Number NA Version V1.0 Issue Summary The following issue has been identified in the ESP32-C5 and ESP32-C61 series chips: When flash and PSRAM are used simultaneously and their bus clock frequencies are different, for example: • Flash operates at 80 MHz while PSRAM operates at 40 MHz (default configuration in ESP-IDF). • Flash operates at 40 MHz while PSRAM operates at 80 MHz. The side running at 80 MHz may experience clock asymmetry, which can lead to system instability. In some cases, a small number of chips may exhibit random crashes. The following scenarios do not have this issue: • Flash and PSRAM both operate at 80 MHz or both at 40 MHz. • PSRAM is not used. Impact Analysis Affected Product Series: This issue affects the ESP32-C5 and ESP32-C61 series of chips. ESP-IDF Affected Versions: 2/3 ESP32-C5 ESP-IDF Branch Affected Commit IDs Affected ESP-IDF Versions master Commits before 12aebb3 (excluded) No official release yet release/v6.0 Commits before cec614e (excluded) v6.0-beta1 release/v5.5 Commits before d892b18 (excluded) v5.5.1-v5.5.3 ESP32-C61 ESP-IDF Branch Affected Commit IDs Affected ESP-IDF Versions master Commits before 526bf61 (excluded) No official release yet release/v6.0 Commits before 23e199d (excluded) v6.0 release/v5.5 Commits before 799c800 (excluded) v5.5.1-v5.5.3 Mitigation ESP-IDF Patched Versions: ESP32-C5 ESP-IDF Branch Fixed Commit IDs Fixed ESP-IDF Versions master 12aebb3 No official release yet release/v6.0 cec614e v6.0-beta2 release/v5.5 d892b18 v5.5.4 ESP32-C61 ESP-IDF Branch Fixed Commit IDs Fixed ESP-IDF Versions master 526bf61 No official release yet release/v6.0 23e199d To be fixed on v6.0.1 release/v5.5 799c800 v5.5.4 3/3 Recommendations for Application Developers If PSRAM is used simultaneously with flash in the application, and the ESP-IDF version used is among the affected versions, it is recommended to upgrade to the fixed ESP-IDF release (see the table above). If you encounter problems during the upgrade process, please provide the IDF version or Commit ID to Espressif. We will confirm and handle related matters as soon as possible.