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J. Nick Koston
935ab42b1e
On some ESP32 boards (especially cheap clones), the eFuse custom MAC area contains random garbage that passes the existing all-zeros/all-ones validation. Additionally, esp_efuse_mac_get_default() can fail with CRC errors, but the return value was being ignored, causing garbage MAC addresses to be advertised via mDNS. This caused Home Assistant to report false "MAC address changed" device conflicts on every boot. Two fixes: - Check return values from eFuse MAC read functions and add a fallback chain: custom MAC -> default MAC -> raw eFuse bytes -> zeroed MAC. - Reject multicast MACs (bit 0 of first byte set) in mac_address_is_valid() since device MACs must always be unicast. Closes https://github.com/esphome/esphome/issues/14501
