Skip to main content

E52 — BLE_BOND_ADD_FAILED

A stored BLE bond could not be restored into the BLE stack.

What happens​

The inner loop breaks and bluetooth_loop returns. The outer bluetooth_timer_task retries after 1 second. The error is recorded once per boot. BLE connection to the FKMTime Display is unavailable until the retry succeeds or the bond data is cleared.

Possible causes​

  • The bond data stored in NVS is corrupted or in a format the current BLE stack cannot parse.
  • A firmware update changed the bond data format.

How to fix​

  1. Clear the stored BLE bond — Use the device's bond-clear option in the settings menu. This removes the corrupted bond from NVS, allowing a fresh pairing.
  2. Re-pair with the FKMTime Display — After clearing, pair again through the BLE pairing menu.
  3. Contact support — Open an issue on GitHub if clearing the bond does not resolve the issue.