I'm trying to turn my raspberry to an iBeacon but I cannot make it transmit with lower power, I've changed Tx power many times, when I use my BLE scanner I see that Tx power has changed but RSSI hasn't at all while with other beacon devices changing transmission power leads to a lower powered measure. Has anyone had the same problem? this is the command that I run.(I've changed C8 to 88, CE, E7 and etc.) sudo hcitool -i hci0 cmd 0x08 0x0008 1E 02 01 1A 1A FF 4C 00 02 15 63 6F 3F 8F 64 91 4B EE 95 F7 D8 CC 64 A8 63 B5 00 00 00 00 C8
The byte you are changing does not control the strength of the output of the transmitter. That byte is referred to by either "tx power" or "measured power". There latter term is more accurate. It is used to communicate to receivers what the expected rssi should be at a range of 1 meter to aid in distance estimates. Again, changing it does not actually change the strength of the transmitter.
Unfortunately, there is no API in the raspberry Pi to alter the strength of the Bluetooth transmitter.