ZBT-2 breaks with update 7.5.1.0

Configuration Zigbee
12

Thread fix for failed ZBT-2 firmware updates (but the method likely also works for Zigbee):

  • Try using the HA GUI - Failed to perform the action update/install. Failed to flash firmware (OpenThread 4.4.0 => 7.2.0)
  • Disconnect the ZBT-2 and move to a PC (Linux + Chrome Canary here)
  • Download the firmware
    Release v2026.02.23 · NabuCasa/silabs-firmware-builder · GitHub
    (I used zbt2_openthread_rcp_2.7.2.0_GitHub-fb0446f53_gsdk_2025.6.2.gbl)
  • Use the OHF web-flasher:
    Install Firmware – Device Toolbox
  • Reconnect to your HA box
  • Restart HA (to be sure hardware detection has completed…)
  • BUG: HA still reports device as requiring an update from 4.4.0 to 7.2.0!
    May be a difference in bootloader version, but definitely NOT v4.4.0!
  • BUG: confirm the HA upgrade to 7.2.0 (which it already has from the web-flasher…)
  • Upgrade worked this time, HA shows no repairs!

Note: The HA GUI showed OpenThread 7.2.0, but the firmware is labelled 2.7.2.0 (OpenThread (RCP) SL-OPENTHREAD/2.7.2.0_GitHub-fb0446f53).

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