Re: Zephyr (v1.13.0) HCI_UART running on nRF52 DK why BD address is always 00:00:00:00:00:00 after power cycle #nrf52832
It is correct that a public address starting with 00:00:00 will not work, it is a reserved IEEE address and the addressing scheme follows that standard, see https://www.iana.org/assignments/ethernet-numbers/ethernet-numbers.xhtml
And in regards to any similar problems with random addresses, this is because as stated in the core version 5 Bluetooth guide:
"At least one bit of the random part of the address shall be 0
At least one bit of the random part of the address shall be 1"
Hcitools was deprecated in 2017 and is no longer maintained and should not be used, this is why by default when building BlueZ with the default build options you don't get these utilities. And depending upon the version of Qt you use, you get a different interface for using Bluetooth, very old versions of Qt have their own GATT implementation, newer versions use BlueZ and with 5.11 it was re-written.