List all available bluetooth interfaces:

hciconfig -a

If you get an error like the following:

Operation not possible due to RF-kill

You’ll need to unblock access to the resource using rfkill. You can unblock all blocked devices like so:

rfkill unblock all

Before doing any iBeacon stuff you should disable scanning:

hciconfig hci0 noscan
hcitool -i hci0 cmd 0x08 0x0008 1E 02 01 1A 1A FF 4C 00 02 15 [ 92 77 83 0A B2 EB 49 0F A1 DD 7F E3 8C 49 2E DE ] [ 00 00 ] [ 00 00 ] C5 00
hcitool -i hci0 leadv
LE set advertise enable on hci1 returned status 12